ALEVEL物理AUnit复习资料之

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alevel物理知识点

alevel物理知识点
A-level物理主要包含以下几个知识点：
1. 经典力学：包括运动学、力学以及能量功率三部分内容。

运动学主要研究物体位置的变化，力学主要研究物体之间的相互作用力，能量功率主要研究能量和做功的问题。

2. 热学：包括热力学和分子物理学。

热力学主要研究热能与机械能、电能等其他形式的能之间的转换，以及转换效率的问题；分子物理学主要研究分子的运动和相互作用，以及与热能相关的现象。

3. 电学：包括静电学和电路学。

静电学主要研究静止电荷之间的相互作用力，以及与电场、电势相关的概念；电路学主要研究电流的形成和流动，以及与电流相关的各种电路元件的作用。

4. 光学：包括几何光学和物理光学。

几何光学主要研究光的直线传播、反射、折射等规律；物理光学主要研究光的波动性质，包括干涉、衍射、偏振等现象。

5. 原子和量子物理：主要研究原子的结构和性质，以及量子力学的基本原理。

包括原子核的结构、放射性衰变、量子力学的波粒二象性等知识点。

以上信息仅供参考，建议查阅A-level物理教材或相关资料获取更全面的信息。

A-LEVEL A2 物理复习资料 particle physics-推荐下载

Section3 particle physics1．The nuclear atom(1)Mass number and atomic number(2)Alpha particle scattering experiment(3)Electrons are accelerated by E and B(4)Write equations using standard nuclear notating(5)Explain why high energies are required to break particles into their constituents and to investigate fine structure(6) de Broglie wavelength λ=h/p(201306R-7)The de Broglie wavelength associated with electrons moving at 2.5 × 106 m s–1 isA .2.9 × 10–4mB .2.4 × 10–8 mC .2.9 × 10–10mD .2.4 × 10–39m (201306-10) The de Broglie wavelength for neutrons used to study crystal structure is 1.2 nm. mass of a neutron = 1.67 × 10–27kgThe speed of these neutrons would beA .3.0 × 106 m s–1 B.3.3 × 102m s–1 C.3.0 × 10–3m s–1 D.3.3 × 10–7m s–1 (201306R-8 )Which of the following is not a valid conclusion from Rutherford’s alpha particle scattering experiment?A .The atom is mainly empty space.B .The mass of the atom is mostly concentrated in the nucleus.C. The nucleus must be positively charged.D .The nucleus must be very small compared to the atom.(201306R-9) Select the row in the table that correctly identifies the composition of a 235U+ ion.92Number of protons Number of neutrons Number of electrons A9214391B9214392C9223591D9323592(201306-1)The nucleus of one of the isotopes of nickel is represented by 6028Ni. Which line correctly identifies a neutral atom of this isotope?Number of protons Number of neutrons Number of electrons A283228B283232C286028D602828（201201-10）The de Broglie wavelength of a moving tennis ball is calculated as 1× 10-33 m. This means that the moving tennis ballA .diffracts through a narrow slit. B.does not behave as a particle.C.does not display wave properties.D.is travelling at the speed of light.(201306R-10) .A transmissionelectron microscope passes abeam of electrons through atiny specimen to form an imageon a viewing screenDue to the wave nature ofelectrons, diffraction occurswhich can blur the image. Toreduce this effect whenviewing a smaller object thebeam must containA .more electrons per second.B .fewer electrons per second.C. faster moving electrons. D .slower moving electrons(201306-13).In an experiment to investigate the structureof the atom, α-particles are fired at a thin metal foil,which causes theα-particles to scatter.(a)(i) State the direction in which thenumber of α-particles detected will be amaximum(ii) State what this suggests about the structure of the atoms in the metal foil.(b) Some α-particles are scattered through180°.State what this suggests about the structure of the atoms in the metal foil.(c)The diagram shows the path of anα-particle passing near to a single nucleus inthe metal foil.(i)Name the force that causesthe deflection of the α-particle.(ii) On the diagram, draw anarrow to show the direction of the force acting on the α-particle at the point where the force is a maximum. Label the force F.(iii) The foil is replaced by a metal of greater proton number.Draw the path of an α-particle that has the same initial starting point and velocity as the one drawn in the diagram.(201301-11) Early in the twentieth century physicists observed the scattering of alpha particles after they had passed through a thin gold foil. This scattering experiment provided evidence for the structure of the atom.(a) State why it is necessary to remove the air from the apparatus that is used for this experiment.(b) From the results of such an experiment give two conclusions that can be deduced about the nucleus of an atom.Conclusion 1Conclusion 2(c) The diagram shows three α-particles ,allwith the same kinetic energy .The path followedby one of the particles is shown . Add to thediagram to show the paths followed by the othertwo particles.(201302-12 )The electron in a hydrogen atom can be described by a stationary wave which is confined within the atom.This means that the de Broglie wavelengthassociated with it must be similar to the size of the atom which is of the order of 10–10 m.(a)(i)Calculate the speed of an electron whose de Broglie wavelength is1.00 × 10–10m. (ii) Calculate the kinetic energy of this electron in electronvolts(b)When βradiation was first discovered ,it was suggested that there were electrons in the atomic nucleus, but it was soon realised that this was impossible because the energy of such an electron would be too great.Suggest why an electron confined within a nucleus would have a much greater energy than the energy calculated in (a)(ii).2．high-energy collisions(1)The role of E in linear particle accelerators(2)r=p/BQ in B(3)⊿E=c2⊿m(4)Units:MeV,GeV,MeV/c2 ,GeV/c2,u(201301-10)The tubes of a linear accelerator (linac) get progressively longer down its length becauseA .the accelerating particles become relativistic.B .the frequency of the applied potential difference changes.C .the accelerating particles must spend the same time in each tube.D .the accelerating particles gain mass（201206-10）As a particle accelerates in a linac, it passes through drift tubes of increasing lengths. This is so thatA.the particle can be given more energy within each tube.B.the frequency of the accelerating voltage can be constant.C.the accelerating voltage can be as high as possible.D.the time spent in the tube by the particle is longer(201306R-6)Charged particles are travelling at a speed v, at right angles to a magnetic field of flux density B. Each particle has a mass m and a charge Q.Which of the following changes would cause a decrease in the radius of the circular path of the particles?A .an increase inB B .an increase in mC .an increase in vD .a decrease in Q (201306-6)A muon has a mass of 106 MeV/c2. The mass of a muon, to two significant figures, isA .1.7 × 10–11 kgB .5.7 × 10–20 kgC .1.9 × 10–28 kg D.1.9 × 10–34 kg (201201-7)The rest mass of a proton is 1.67 × 10–27 kg. This mass, in MeV/c2 is approximatelyA .2.4 × 10–20 B.3.1 × 10–6 C.1.0 D .940(201106-10)The Large Hadron Collider is designed to accelerate protons to very high energies for particle physics experiments. Very high energies are required toA .annihilate hadrons. B.collide hadrons.C .create particles with large mass. D.produce individual quarks(201206-13) An electron and a positron annihilate with the emission of two photons of equal energy. Calculate the wavelength of the photons.(201201-17) (d) The technology suggested in the science fiction series, Star Trek, for powering the Starship Enterprise relied on antimatter. When an anti-hydrogen atom meets a hydrogen atom, they annihilate and produce energy.(i)How much energy, in joules, would be produced by the annihilation ofjust 1 milligram of anti-hydrogen atoms?(ii) Anti-protons are required to produce anti-hydrogen atoms. The total production of anti-protons on Earth over the past 25 years adds up to only a few nanograms.Suggest why so little anti-matter has been created3. Particle accelerators(1) E and B in cyclotron particle accelerators(2) Relativistic effects at speeds near c(201306-9)A cyclotron is a type of particle accelerator. It consists of two metal Dees which are connected to a high frequency voltage supply and are in a strong magnetic field. The particles change their speed becauseA.of the magnetic field they are in.B.the voltage supply is alternating.C.there is a potential difference between the two Dees.D.the magnetic field is at right angles to the Dees.(201306R-11)*11 The diagram shows the basic structure of a cyclotron.With reference to the magnetic field and the alternating potential difference explain how the cyclotron produces a beam of high speed particles.4. Particle theory(1) E and B in particle detectors(2) Charge energy and momentum are conserved in interactions between particles andhence interpret records of particle tracks(3) In the standard quark-lepton model each particle has a corresponding anti-particle meson:quark-anti-quark pairs baryon :quark triplets(4) Write and interpret equations using Standard symbols(201206-9)A pion can decay to produce two leptons. Which one of the following is possible?A.π+→e+ + v e B .π0→e– + v e C.π+→e++ e– D π0→π++ e–(201201-8)A positive kaon (K+) is a meson which includes a strange quark. Its structure could beA . u B. us C. D .usds s d d(201201-9) The K+ is likely to decay tov vA.π+ + μ– + μB. π++π0Cπ++π– D π0 + μ– +μ(201306-7 )The diagram shows the tracks from an event at a point P in a bubble chamber. A magnetic field is directed into the page. The tracks cannot show the production of a proton-antiproton pair with equal kinetic energies becauseA .the curvature is perpendicular to the magnetic field.B .the tracks curve in different directions.C. the tracks have different curvatures.D .there is no track before point P(201306-11)Scientists studying anti-matter recently observed the creation of a nucleus of anti-helium 4, which consists of two anti-protons and two anti-neutrons. The diagram represents the path of a proton through a magnetic field starting at pointX.Add to the diagram the path of an anti-helium 4 nucleus also startingat point X and initially travelling at the same velocity as theproton.Explain any differences between the paths.(201306-14)The photograph shows tracks in aparticle detector.(a) Explain the role of a magnetic field in a particledetector(b) Explain how you can tell that track XY was produced by a particle moving fromX to Y rather than from Y to X.(c)The particle that produced track XY was a π+.Deduce the direction of the magnetic field in the photograph(d) At Y, the π+ decayed into a positively charged muon (μ+) and a muon neutrino. The μ+ has a very short range before decaying into various particles, including a positron which produced the final spiral.(i) Give two reasons why you can deduce that the muon neutrino is neutral.(ii) Explain the evidence from the photograph for the production of the muon neutrino at Y.(201306R-14) .Hadrons are a group of particles composed of quarks. Hadrons can be either baryons or mesons.(a) (i) State the quark structure of a baryon.(ii) State the quark structure of a meson.(b) State one similarity and one difference between a particle and its antiparticle. Similarity:Difference :(c) (i) The table gives some of the properties of up, down and strange quarks.Type of quark Charge/e Strangenessu+2/30d-1/30s-1/3-1One or more of these quarks combine to form aΚ+, a meson with a strangeness of +1.Write down the quark combination of theΚ+..(ii)TheΚ+can decay in the following way Κ+→ µ++ vµK–is the antiparticle of the K+ . Complete the equation below by changing each particle to its corresponding antiparticle in order to show an allowed decay for the K–meson.Κ－→(iii)The rest mass of theΚ+ is 494 MeV/c2Calculate, in joules, how much energy is released if a Κ+ meets and annihilates a K–(201306-12)The table gives some of the properties of the up, down and strange quarks.Type of quark Charge/e Strangenessu+2/30d-1/30s-1/3-1There are nine possible ways of combining u, d and s quarks and their antiquarks to make nine different mesons. These are listed belowu d s d u s s u du u u d d d s s s (a) From the list select the four strange mesons and state the charge and strangeness of each of them.Meson Charge/e Strangeness(b) Some of the mesons in the list have zero charge and zero strangeness.Suggest what might distinguish these mesons from each other.*14 A bubble chamber is a particle detector which makes use of electric and magnetic fields. Explain the role of electric and magnetic fields in a particle detector. (201301-17)In 2011 physicists at the Relativistic Heavy Ion Collider (RHIC) announced the creation of nuclei of anti-helium-4 which consists of anti-protons and anti-neutrons instead of protons and neutrons(a) ‘Ordinary’ helium-4 is written as 42He.What do the numbers 4 and 2 represent?(b) In the RHIC experiment, nuclei of gold 19779Au travelling at speeds greater than2.99 × 108m s–1, in opposite directions, collided, releasing energies of up to 200 GeV. After billions of collisions, 18 anti-helium nuclei had been detected.(i) What is meant by ‘relativistic’ in the collider’s name?(ii) State why it is necessary to use very high energies in experiments such as these. (iii) Show that the mass of a stationary anti-helium nucleus is about 4 GeV/c2(iv) State why the small number of anti-helium nuclei produced only survive for a fraction of a second.(v) A slow moving anti-helium nucleus meets a slow moving helium nucleus. If they were to combine to produce 2 high energy gamma rays, calculate the frequency of each gamma ray.(c) There are two families of hadrons, called baryons and mesons. Baryons such asprotons are made of three quarks.(i) Describe the structure of a meson(ii) Up quarks have a charge of +2/3e and down quarks a charge of –1/3e.Describe the quark composition of anti-protons and anti-neutrons and use this to deduce the charge on each of these particles.（201206-18）18 (a) Physicists were able to confidently predict the existence of a sixth quark. State why(b) The mass of the top quark was determined by an experiment. Collisions between protons and anti-protons occasionally produce two top quarks.(i) How do the properties of a proton and an anti-proton compare?(ii) After the collision the two top quarks move in opposite directions with the same speed. Explain why.(c) The two top quarks decay rapidly into two muons and four jets of particles. These can be detected and their momenta measuredThe diagram shows an end-on view of the directions of the four jets (J1 to J4) of particles. The two muons are shown as μ1and μ2. A muon neutrino is also produced but cannot be detected, so is not shown. Each momentum is measured inGeV/c.(i)Explain why GeV/c is a valid unit for momentum.(ii) The vector diagram shown below is not complete. Add to the diagram arrows to represent the momenta of J3 and J4.(iii) Complete the diagram to determine the magnitude of the momentum of the muon neutrino.(iv) Show that the total energy of all the products of this event is about 300 GeV. (v) Deduce the mass of a top quark in GeV/c2.(vi) Suggest why it took a long time to find experimental evidence for the top quark.。

A-LEVEL物理A2Unit5复习资料5

Section 5 nuclear decay：Revision spread ：1.nuclear radiationCheckpoints :（1) show an awareness of the existence and origin of background radiation ，past and present.（2） investigate and recognize nuclear radiations (αβγ）from theirpenetrating power and ionizing ability 。

（3） describe the spontaneous and random nature of nuclear decay.（4) determine the half-lives of radioactive isotopes graphically。

(5） recognize and use the expressions for radioactive decay dN/dt=—λN,λ=ln2/t1/2 N=Ne—λt(6）discuss the applications of radioactive materials，including ethical and environmental issues。

（201306r—2）In a famous thought experiment, Schrödinger imagined that a cat is locked in a box, along with a radioactive atom that is connected to a tube containing a deadly poison。

If the atom decays, it causes the tube to smash and the cat to die. The random nature of radioactive decay means that the radioactive atom willA 。

alevel物理aqa第一章知识点汇总

alevel物理aqa第一章知识点汇总In AQA A-Level Physics, the first chapter covers several key concepts, including mechanics, motion, forces, energy, and materials. 这一章是物理课程的基础，对于学生来说非常重要。

其中，力、运动、材料和能量等相关概念是学生需要深入理解和掌握的重要内容。

Understanding these concepts lays the foundation for later chapters and topics in physics. 理解这些基本概念对于学生在后续学习物理课程时起到了很重要的作用。

One of the key areas covered in this chapter is mechanics, which focuses on the study of motion and the forces that cause motion. 这一章重点讲述了力学，它专注于研究物体的运动以及导致这种运动的力。

Students will learn about Newton's laws of motion, the concept of momentum, and circular motion. 学生们需要理解牛顿运动定律、动量的概念以及圆周运动等内容。

These concepts provide a framework for understanding how objects move and interact with one another. 这些概念为学生们提供了分析物体运动和相互作用的框架。

Another important topic in the first chapter is energy, including different forms of energy and the conservation of energy. 另一个重要的主题是能量，包括不同形式的能量以及能量守恒定律。

alevel物理知识点总结

alevel物理知识点总结IntroductionA-level Physics is a comprehensive course that covers a wide range of topics in physics, from classical mechanics and thermodynamics to quantum physics and astrophysics. It is a challenging subject that requires a sound understanding of mathematical concepts and scientific principles. In this summary, we will cover some of the key knowledge points in A-level Physics, including important theories, laws, and equations.Classical MechanicsClassical mechanics is the branch of physics that deals with the motion of objects and the forces that act on them. It is based on the principles of Newtonian mechanics, which were developed by Sir Isaac Newton in the 17th century. The key concepts in classical mechanics include:- Newton's Laws of Motion: Newton's three laws of motion are fundamental principles that describe the behavior of objects in motion. The first law states that an object at rest will remain at rest, and an object in motion will remain in motion at a constant velocity, unless acted on by an external force. The second law relates the force acting on an object to its mass and acceleration, and the third law states that for every action, there is an equal and opposite reaction.- Conservation of Energy: The principle of conservation of energy states that the total energy in a closed system remains constant over time. This includes both kinetic energy (energy of motion) and potential energy (energy due to an object's position).- Conservation of Momentum: The principle of conservation of momentum states that the total momentum of an isolated system remains constant, provided no external forces act on the system.ThermodynamicsThermodynamics is the branch of physics that deals with the relationships between heat, work, and energy. It is a fundamental concept in the study of physical systems and their behavior. The key concepts in thermodynamics include:- The First Law of Thermodynamics: The first law of thermodynamics, also known as the principle of conservation of energy, states that the total energy of an isolated system remains constant. This means that energy cannot be created or destroyed, only transferred from one form to another.- The Second Law of Thermodynamics: The second law of thermodynamics states that the total entropy of an isolated system will always increase over time. This implies that processes occurring in nature are irreversible, and that there is a directionality to the flow of energy.- The Carnot Cycle: The Carnot cycle is a theoretical thermodynamic cycle that represents the most efficient possible heat engine, and serves as a benchmark for the maximum efficiency of real-world heat engines.ElectromagnetismElectromagnetism is the branch of physics that deals with the relationship between electricity and magnetism, and the behavior of charged particles. It is a fundamental concept in the study of electromagnetics. The key concepts in electromagnetism include:- Coulomb's Law: Coulomb's law describes the force between two point charges, and is given by the equation F = k * (q1 * q2) / r^2, where F is the force, k is the electrostatic constant, q1 and q2 are the magnitudes of the charges, and r is the distance between the charges.- Ampere's Law: Ampere's law describes the relationship between an electric current and the magnetic field it generates. It is given by the equation ∮B * dl = μ0 * I, where B is the magnetic field, dl is an infinitesimal element of length, μ0 is the permeability of free space, and I is the electric current.Quantum PhysicsQuantum physics is the branch of physics that deals with the behavior of particles at the atomic and subatomic level. It is a highly complex and abstract field of study, and has led to many groundbreaking discoveries in physics. The key concepts in quantum physics include:- Schrödinger's Wave Equation: Schrödinger's wave equation describes the behavior of quantum particles by treating them as waves of probability. It is used to calculate the probability distribution of a particle's position and momentum.- The Heisenberg Uncertainty Principle: The Heisenberg uncertainty principle states that it is impossible to know both the position and momentum of a particle with absolute certainty. There is an inherent uncertainty in the measurement of these quantities, which is given by the equation Δx * Δp ≥ h/4π, where Δx is the uncertainty in position, Δp is the uncertainty in momentum, and h is Planck's constant.AstrophysicsAstrophysics is the branch of physics that deals with the study of celestial objects and the universe as a whole. It involves the application of physical principles to understand the behavior of stars, galaxies, and other astronomical phenomena. The key concepts in astrophysics include:- The Big Bang Theory: The Big Bang theory is the prevailing cosmological model for the origin of the universe. It states that the universe began as a singularity and has been expanding ever since, leading to the formation of galaxies, stars, and planets.- The Hubble Law: The Hubble law describes the relationship between the distance to a galaxy and its recessional velocity, and is given by the equation v = H0 * d, where v is the recessional velocity, d is the distance, and H0 is the Hubble constant.ConclusionA-level Physics covers a wide range of topics and concepts, from classical mechanics and thermodynamics to quantum physics and astrophysics. It is a challenging subject that requires a deep understanding of mathematical principles and scientific theories. This summary has covered some of the key knowledge points in A-level Physics, and serves as a useful reference for students and enthusiasts of physics.。

alevel物理a2知识点

alevel物理a2知识点
A2阶段物理知识点包括以下内容：
1. 圆周运动：研究物体绕固定点旋转的基本规律，如角速度、周期等。

2. 万有引力场：描述物体在地球或其他天体附近受到的引力作用，以及物体之间的万有引力关系。

3. 理想气体：研究理想气体状态方程和理想气体定律，包括压强、温度、体积等之间的关系。

4. 温度：研究温度的概念、温标的建立以及温度与热量、内能之间的关系。

5. 物质的热运动：描述分子的无规则运动和热传导的基本概念，如分子动理论、热容等。

6. 振动：研究简谐振动的规律，包括振幅、频率、相位等。

7. 通讯：介绍电磁波的传播和通讯方式，如无线电波、光波等。

8. 电容：研究电容的概念和电容器的充放电过程，包括电容器、电容等。

9. 电子元件：介绍基本的电子元件，如电阻、电容、电感等及其特性。

10. 磁场：研究磁场的基本概念和磁力作用，如磁场强度、磁通量等。

11. 电磁感应：描述电磁感应现象和法拉第电磁感应定律，包括感生电动势等。

12. 交流电：研究交流电的产生、传输和利用，如交流电的波形、频率等。

13. 量子物理：介绍量子力学的基本概念和原理，如波粒二象性、量子态等。

此外，A2阶段物理知识点还包括AS阶段的所有内容，如物理量和单位、测量技术、运动学、动力学、力密度压强、功能量功率、固体形变、波、波的叠加、电场、电流、直流电路等。

同时，A2阶段还有实验技能考察，注重综合的科学实验素养考察，如设计实验，分析和统计检验等能力。

以上知识点只是简要列举，具体内容可能因教材或考试大纲而有所不同。

建议查阅相关教材或考试大纲以获取更详细的信息。

ALevel物理知识点梳理系列一

A L e v e l物理知识点梳理系列一IMB standardization office【IMB 5AB- IMBK 08- IMB 2C】A-L e v e l物理知识点梳理系列（一）物理量及单位(physicalquantitiesandunits)A-level物理AS阶段涵盖了物理量、测量、运动学、力学、功与能量、物质与材料学、波、电学以及核物理等九大版块。

本次知识梳理将对各个板块所涵盖的知识点、重要公式以及相关的典型真题进行精讲精练。

希望通过本次的系统复习，同学们能够对各章节内容掌握得更加清晰透彻，形成知识体系，在解题过程中能够及时将题目与其背后所考察的知识点对应起来。

本期将对物理量(physicalquantitiesandunits)进行专题讲解，这一部分是AS物理的开篇内容，与其他章节比相对简单，但又是学好后续章节的基础。

CIE物理paper1的前两小题及paper2的第一题一般会考察此章节内容。

一、矢量与标量Vectorsandscalarsscalar:physicalquantitythathasmagnitudeonly.vector:physicalquantitythathasmagnitudeanddirection.区分矢量与标量的唯一标准为所描述的物理量是否包含方向(direction)这一要素.包含方向要素则为矢量(vector)，如位移(displacement)、速度(velocity)等；若仅用大小(ma gnitude)即可描述，则该物理量为标量，如温度(temperature),功率(power)等。

真题解析S041WhichpaircontainsonevectorandonescalarquantityAdisplacement:accelerationBforce:kineticenergyCmomentum:velocityDpower:speed此题为04年春季paper1的第一小题。

alevel物理知识点盘点

alevel物理知识点盘点英文回答：Physics is a fascinating subject that explores the fundamental principles of the universe. As an A-level student, there are several key topics that you will cover in your physics course. Let's take a look at some of the important knowledge points in A-level physics.1. Mechanics: Mechanics is the study of motion and forces. You will learn about concepts such as Newton's laws of motion, momentum, energy, and circular motion. For example, you will understand how an object's velocity changes when a force is applied to it, or how the conservation of momentum works in collisions.2. Waves: Waves are a common phenomenon in nature, and in physics, you will study the properties and behavior of waves. This includes topics like wave motion, wave interference, and the different types of waves such assound waves and electromagnetic waves. For instance, youwill learn how waves can be reflected, refracted, or diffracted, and how they can be used in variousapplications like communication systems.3. Electricity and Magnetism: This topic deals with the principles of electricity and magnetism. You will learn about electric circuits, Ohm's law, electromagnetic induction, and the behavior of magnetic fields. For example, you will understand how electric current flows in a circuit and how magnetic fields can be used to generate electricity.4. Quantum Physics: Quantum physics is a branch of physics that deals with the behavior of particles at the atomic and subatomic level. You will learn about concepts such as wave-particle duality, quantum mechanics, and the uncertainty principle. For instance, you will explore how electrons can exist in multiple energy statessimultaneously and how the behavior of particles can be described by probability.5. Thermodynamics: Thermodynamics is the study of heatand energy transfer. You will learn about topics like the laws of thermodynamics, heat engines, and entropy. For example, you will understand how energy is transferred between systems and how heat engines can convert heat into useful work.中文回答：物理是一门令人着迷的学科，探索着宇宙的基本原理。

alevel 物理u4知识点

A Level 物理 Unit 4 知识点在 A Level 物理的 Unit 4 中，学生将会学习一些重要的知识点和概念，这些知识点不仅有助于学生学习物理的基础，也对他们今后的学习和职业发展有着重要的影响。

以下是一些在 A Level 物理 Unit 4 中涉及的重要知识点：1. 电磁感应- 法拉第/楞次定律- 动生电动势- 自感和互感- 安培环路定律- 电动机和发电机的工作原理2. 交流电- 交流电的特点- 交流电路的分析- 交流电的功率和功率因数- 交流电的变压器和变压器原理- 交流电的应用3. 光学- 几何光学和物体成像- 光的波动性和干涉- 光的偏振和偏光- 光的色散和光谱- 光波的双缝衍射实验4. 半导体和电子学- 半导体的导电性- PN 结和二极管- 晶体管和运算放大器- 信号处理和数字电子学- 半导体器件的应用5. 核物理- 放射性衰变- 核裂变和核聚变- 辐射和辐射测量- 核反应堆和核能发电- 医学应用和核武器6. 环保与能源- 可再生能源和非可再生能源 - 能源转换和能源效率- 环保技术和环境影响评价- 可持续发展的理念和实践- 环保和能源政策以上知识点涵盖了 A Level 物理 Unit 4 的主要内容，学生需通过对这些知识点的掌握来提高对物理学科的理解和认识。

这些内容也对现实生活和社会发展具有重要的意义，因此学生应该认真学习并深入理解这些知识点，以便将来在科研和工程实践中能够运用这些知识。

在 A Level 物理 Unit 4 中，学生将深入学习电磁感应、交流电、光学、半导体和电子学、核物理以及环保与能源等领域的知识。

这些知识点不仅仅是理论概念，更是与现实生活息息相关的科学原理和工程应用。

下面将进一步展开对这些知识点的详细讨论和探究。

1. 电磁感应电磁感应是电磁学中的重要概念，它描述了磁场和电场相互作用所产生的现象。

在学习电磁感应时，学生将学习到法拉第/楞次定律，即当一个导体相对于磁场的相对运动时，就会在导体两端产生感应电动势。

A-Level物理知识点分享

A-Level物理知识点分享今天编辑来教同学们学习A-Level物理考试中的一些解题思路，让我们来看看在A-Level物理考试中占很大分值的画图题该如何攻破？A-Level物理学科内容大致包含以下几个方面：力学、电磁学、波、热学、光学、材料、基本粒子、相对论和量子物理等等几大部分。

题型分别有选择题、实验题以及计算题等。

今天我们来看看A-level物理的画图、计算题解题四步大法：第一步，就是审清题目，按照题目要求画出示意图。

比如同学们头疼的Newton's second law，看到题目不管会不会，直接把Free-body force diagrams画出来。

不会画咋办呢？题目里不是有原图吗，照抄就可以了。

所以，这一步最重要的，其实就是强迫自己理解题目的意思！第二步就是把题目中所有已知量写到解题步骤的前面。

在这里要提醒大家注意了，所有已知量啊，包括隐藏的，不隐藏的，统统地写成字母=数字和单位形式，比如：F=1.0 Nm=20 kg第三，在列出已知量之后，下面要做的就是带入公式！什么，你觉得这步最难？并没有，A-level考试和国内高考最大的区别是什么？老外给公式表啊！英国小伙伴不需要背公式的。

当你迷惑于用哪个公式的时候，请翻到考卷第一页，照着抄会不会啊！最后一步，那就是把已知量，未知量写到一起，等式左右在一起，求个解这道题不就出来了！一元一次方程或者二元一次方组，就是这些数学方程式不会算？如果真的不会算，那怎么办？嗯，这是数学问题……在掌握了这四步大法后，我们贡献出画图题的解题神技。

我们来做一道画图题，请先看一下题干：好的，现在题目问题来了：（a）和（b）其实是一个知识点。

就是判断力的方向。

我们在此应用了Fleming's left-hand rule，受力方向向下。

这里，很多同学分不清楚，Fleming'sleft-hand rule与Fleming's right-hand rule的区别，什么时候用左手，什么时候用右手。

alevel物理各单元知识

alevel物理各单元知识第一单元：力学力学是物理学的基础，也是Alevel物理的第一个单元。

在这个单元中，我们需要学习牛顿定律、动量守恒、万有引力等知识点。

此外，我们还需要掌握一些基本的数学工具，如向量、微积分等。

第二单元：电学电学是Alevel物理的第二个单元，它涵盖了静电学、电流、电场、电势等知识点。

在这个单元中，我们需要掌握欧姆定律、基尔霍夫定律、磁感应强度等概念，并能够运用它们解决实际问题。

第三单元：热学热学是Alevel物理的第三个单元，它主要涵盖了热力学和统计物理学两个方面。

在这个单元中，我们需要掌握温度、热量、热力学第一定律、热力学第二定律等概念，并能够应用它们解决实际问题。

第四单元：光学光学是Alevel物理的第四个单元，它主要涵盖了光的传播、反射、折射、干涉等知识点。

在这个单元中，我们需要掌握光的波动性和粒子性、杨氏双缝干涉、薄膜干涉等概念，并能够运用它们解决实际问题。

第五单元：波动波动是Alevel物理的第五个单元，它主要涵盖了机械波和电磁波两个方面。

在这个单元中，我们需要掌握波的定义、波的传播、波的衍射等概念，并能够应用它们解决实际问题。

第六单元：原子物理原子物理是Alevel物理的第六个单元，它主要涵盖了原子结构、放射性衰变等知识点。

在这个单元中，我们需要掌握原子结构、原子核结构、放射性衰变等概念，并能够应用它们解决实际问题。

第七单元：粒子物理粒子物理是Alevel物理的第七个单元，它主要涵盖了基本粒子和相互作用等知识点。

在这个单元中，我们需要掌握基本粒子的分类、相互作用的类型等概念，并能够应用它们解决实际问题。

第八单元：天体物理天体物理是Alevel物理的最后一个单元，它主要涵盖了行星运动、恒星演化等知识点。

在这个单元中，我们需要掌握行星运动规律、恒星演化过程等概念，并能够应用它们解决实际问题。

Alevel物理涉及的知识点非常广泛，但是通过对每个单元的系统学习和掌握，我们可以轻松应对考试。

unit4 A-LEVEL A2 物理复习资料

Unit4 Physics on the MoveSection2 electric and magnetic field1.electrostatics(1)Electric field(2)E=F/Q unit(3)Electric field line(radial)(4)F=KQ1Q2/r2(5)E=kQ/r2(201306r-4) Two protons, separated by a distance x, experience a repulsive force F.If the separation is reduced to x/3 the force between the protons will beA F/9B F/3C 3FD 9F(201206-4) A unit of electric field strength isA . J C–2B . N m2C–2 C. N m C–1 D . N C–1(201206-11)The positively charged particles in the solar wind are accelerating away from the Sun. Some scientists have therefore concluded that the Sun is positively charged.(a)Explain this conclusion.(b) The circle below represents the Sun.Complete the diagram to show the electric field produced by a positively-charged Sun.（201001-11）The diagram represents a proton(a) Draw lines to represent its electric field.(b) Calculate the electrostatic force on the electron in a hydrogen atom.Average distance between proton and electron = 5.4 x 10–11 m(201301-14) Two identical table tennis balls, M and N, are attached to non-conducting threads and suspended from a point P. The balls are each given the same positive charge and they hang as shown in the diagram. The mass of each ball is 2.7 g. (a) Draw a free-body force diagram for ball M, label your diagram with the names ofthe forces.(b) (i) Show that the tension in one of the threads is about 3 ×10–2N. (ii) Show that the electrostatic force between the balls is about 2 × 10–2 N(iii) Calculate the charge on each ball.(c) State and explain what would have happened if the charge given to ball M was greater than the charge given to ball N.(201106-16) (a) Sketch the electric field surrounding the gold nucleus drawn below.(b) The spreadsheet shown approximately models the behaviour of an alpha particleas it approaches a gold nucleus.The proton number of gold is 79. mass of alpha particle=6.64×10–27kg(i)Show how cell B3 is calculated.(ii) Show how cell D5 is calculated.(iii) Show how cell E6 is calculated(iv) Suggest a value for the maximum radius of a gold nucleus based on the results from this spreadsheet.*(c) Describe the conclusions Rutherford reached about the structure of gold atoms asa result of the alpha particle scattering experiments.2.capacitors(1) structure(2) Uniform electric field(3) E=V/d C=Q/V(4) W=1/2QV graph W=1/2CV2（201306-3）Two parallel, conducting plates are connected to a battery. One plate is connected to the positive terminal and the other plate to the negative terminal. The plate separation d is gradually increased while the plates stay connected to the battery. Select the graph that shows how the electric field strength E between the plates varies with separation d.(201206-5)A capacitor is discharging through a resistor and the time constant is 5.0 s. The time taken for the capacitor to lose half its charge isA 0.14 sB 0.81 sC 3.2 sD 3.5s（201206-7）The diagram shows two parallel plates a distance d apart. There is a potential difference V across the two plates. A particle, charge – q, is placed between the plates as shown. The particle is attracted to the positive plate and moves through a distance x.Which of the following expressions gives the work done on the particle as it moves through the distance x ?A .qV/xdB .qVx/dC .V/xdq D. xV/qd(201306r-5)The capacitor shown in the circuit below is initially charged to a potential difference (p.d.) V by closing the switch. The power supply has negligible internal resistance.The switch is opened and the p.d. across the capacitorallowed to fall. A short time later the switch is closed again.Select the graph that shows how the p.d. across thecapacitor varies with time, after the switch is opened(201201-11) 1 (a) Explain what is meant by a uniform electric field.(b) Describe how a uniform electric field can be demonstrated in a laboratory.(201201-16)The diagram shows a circuit that includes a capacitor.(a)(i) Explain what happens to thecapacitor when the switch is closed.(ii) The potential difference (p.d.) across the resistor rises to a maximum as the switch is closed. Explain why this p.d. subsequently decreases to zero.*(b) One type of microphone uses a capacitor. The capacitor consists of a flexible front plate (diaphragm) and a fixed back plate. The output signal is the potential difference across the resistor.The sound waves cause the flexible front plate to vibrate and change the capacitance. Moving the plates closer together increases the capacitance. Moving the plates further apart decreases the capacitance.Explain how the sound wave produces an alternating output signal(c) A microphone has a capacitor of capacitance 500 pF and resistor of resistance 10 MΩ. Explain why these values are suitable even for sounds of the lowest audible frequency of about 20 Hz（201306-14）A student is investigating how the potential difference across acapacitor varies with time as the capacitor is charging. He uses a 100 μF capacitor, a5.0V d.c. supply, a resistor, a voltmeter and a switch.(a)(i) Draw a diagram of the circuit he should use(ii) Suggest why a voltage sensor connected to a data logger might be a suitable instrument for measuring the potential difference across the capacitor in this investigation.(b) Calculate the maximum charge stored on the capacitor.(c) The graph shows how the potential difference across the capacitor varies with time as the capacitor is charging.(i)Estimate the average charging current over the first 10 ms.(ii) Use the graph to estimate the initial rate of increase of potential difference across the capacitor and hence find the initial charging current.(201206-16)16 A student is investigating capacitors. She uses the circuit below to check the capacitance of a capacitor labelled 2.2 μF which has a tolerance of ±30%. The switch flicks between contacts, X and Y, so that the capacitor charges and discharges f times per second.(a)The capacitor must discharge fullythrough the 100Ωresistor.(i) Explain why 400 Hz is a suitablevalue for f.(ii) Show that the capacitance C can be given by C=I/fVwhere I is the reading on the ammeter and V is the reading on the voltmeter.(iii) The student records I as 5.4 mA and V as 5.0 V.Calculate the capacitance C.(iv) Explain whether you think this value is consistent with the tolerance given for this capacitor.(b) Calculate the energy stored on the capacitor when it is charged to a potential difference of 5.0 V(201306r-15)15 A particular experiment requires a very large current to be provided for a short time.(a) An average current of 2.0 × 103 A is to be supplied to a coil of wire for a time of1.4 × 10–3s. The resistance of the coil is 0.50Ω.(i) Show that the charge that flows through the coil during this time is about 3 C.(ii) The circuit shows how a capacitor could be charged andthen discharged through the coil to provide the current.The circuit contains a capacitor of capacitance 600μF.Thiscapacitor is suitable to provide the current for 1.4 × 10–3s.Explain why the capacitor is suitable.(b) It can be assumed t hat the 600 μF capacitor completely discharges in 1.4× 10–3s.(i) Calculate the potential difference of the power supply.(ii) Calculate the average power delivered to the coil in this time.(201306r-17)A teacher uses an electron beam tube to demonstrate the behaviour of electrons in an electric field. The diagram shows the path of an electron in a uniform electric field between two parallel conducting plates.(b)Mark on the diagram the direction of the electric field.(b) The conducting plates are 5.0 cm apart and have a potential difference of 160 V across them. Calculate the force on the electron due to the electric field.(c) Explain why the path of the electron is curved between the plates and straight when it has left the plates.(d) The electron was initially released from a metal by thermionic emission and then accelerated through a potential difference before entering the region of the electric field.(i) State what is meant by thermionic emission.(ii) In order to be able to just leave the plates as shown, the electron must enter the electric field between the plates with a speed of 1.2 ×107m s–1.Calculate the potential difference required to accelerate an electron from rest to this speed. (201001-13 )An uncharged capacitor is connected into a circuit as shown.(a) Describe what happens to the capacitor when the switch S is closed.(b) A student models the behaviour of the circuit using a spreadsheet. The student uses a 100 µF capacitor, a 3.00 kΩ resistor and 5.00 V power supply. The switch is closed at time t = 0 s.(i) Explain how the value in cell C4 is calculated.(ii) Explain how the value in cell E3 is calculated.(c) The graph shows how the spreadsheet current varies with time.(i) Use the graph to show that the time constant is approximately consistent with the component values.(ii) The student thinks that the graph is an exponential curve. How would you use another graph to confirm this(201101-15 )A student sets up the circuit shown in the diagram(a)(ⅰ)She moves switch S from X to Y. Explainwhat happens to the capacitor .(ⅱ)On the axis below ,sketch a graph to howthe current in the ammeter varies with time fromthe moment the switch touches Y. Indicate typicalvalues of current and time on the axes of yourgraph.(ⅲ)Describe how the graph would appear when theswitch is moved back to X .(c)Calculate the maximum energy stored on the capacitor in this circuit. (c)The student wants to use this circuit to produce a short time delay ,equal to the time it takes for the potential difference across the capacitor to fall to 0.07 of its maximum value.Calculate this time delay(201106-13 )A student needs to order a capacitor for a project. He sees this picture on a web site accompanied by this information: capacitance tolerance ±20%.Taking the tolerance into account, calculate(a) the maximum charge a capacitor of this type can hold.(b) the maximum energy it can store.。

ALevel物理知识点梳理系列一

A-L e v e l物理知识点梳理系列（一）物理量及单位 ( physical quantities and units)A-level物理AS阶段涵盖了物理量、测量、运动学、力学、功与能量、物质与材料学、波、电学以及核物理等九大版块。

本次知识梳理将对各个板块所涵盖的知识点、重要公式以及相关的典型真题进行精讲精练。

本期将对物理量 ( physical quantities and units) 进行专题讲解，这一部分是AS物理的开篇内容，与其他章节比相对简单，但又是学好后续章节的基础。

CIE物理paper1的前两小题及paper2的第一题一般会考察此章节内容。

一、矢量与标量Vectors and scalarsscalar: physical quantity that has magnitude only.vector: physical quantity that has magnitude and direc tion.区分矢量与标量的唯一标准为所描述的物理量是否包含方向(d irection)这一要素. 包含方向要素则为矢量(vector)，如位移(displacement)、速度(velocity)等；若仅用大小(magnitude) 即可描述，则该物理量为标量，如温度(temperature),功率(power)等。

真题解析S 041 Which pair contains one vector and one scalar quanti ty?A displacement : accelerationB force : kinetic energyC momentum : velocityD power : speed此题为04年春季paper1的第一小题。

alevel 物理u4知识

alevel 物理u4知识
在A Level物理U4部分，学生将会学习到以下知识点：
1. 电场和电场线：电场是一种空间中的力场，电荷在其中受到力的作用。

电场线和电场强度是描述电场特性的重要概念。

2. 磁场和磁场线：磁场是磁力作用的场，磁力线或磁场线是描述磁场特性的图形。

学生将学习到磁场的性质、来源以及磁场对电流和磁铁的影响。

3. 电磁感应：这是电磁学中一个重要的概念，描述了当磁场发生变化时会在导体中产生电动势的现象。

学生将学习到法拉第电磁感应定律和楞次定律等基本原理。

4. 交流电和交流电路：交流电是一种电流随时间周期性变化的电流，广泛应用于电力供应和电子设备中。

学生将学习到交流电的特性、交流电路的分析方法以及交流电机的工作原理。

5. 麦克斯韦方程组：麦克斯韦方程组是描述电磁波传播的方程组，包括波动方程、洛伦兹力方程和电荷守恒方程等。

学生将学习到这些方程的物理意义和应用。

6. 光的干涉和衍射：光的干涉和衍射是光的波动性质的体现，学生将学习到这些现象的基本原理和应用，如干涉仪和衍射光栅等。

7. 原子和量子物理：学生将学习到原子结构和量子力学的初步知识，包括原子能级、波函数、量子数等概念。

以上是A Level物理U4部分的主要知识点，通过学习这些内容，学生将建立起对电场、磁场、电磁波以及光的深入理解，为进一步学习物理和其他科学学科打下坚实的基础。

alevel物理考试详解(一)

A Level物理考试详解1. A Level物理考试概述- A Level物理考试是一项涵盖广泛知识的考试，旨在考察学生对于物理学各方面的理解和应用能力。

- 考试内容涵盖力学、电磁学、热力学、光学等多个领域，考生需要全面掌握这些知识，并能够灵活运用于解决问题。

2. 考试结构- A Level物理考试通常包括选择题、填空题和解答题等不同类型的题目。

- 选择题考察考生对基础知识的掌握程度，填空题则更注重对公式和数据的熟练运用，解答题则需要考生展示深入理解和解决问题的能力。

3. 备考重点- 理解基本原理：力学、电磁学、热力学等领域的基本原理是物理考试的重点，考生需要通过理论学习和实践操作，全面理解这些原理。

- 训练解题能力：考试中的解答题需要考生具备较强的分析和推理能力，因此平时需要多做相关题目进行训练，提升解题能力。

- 熟练运用公式：物理考试中公式的运用非常重要，考生需要熟记各个公式，并能够熟练灵活地应用于解题过程中。

4. 解题技巧- 仔细审题：在考试中，仔细审题是非常重要的，考生需要明确题目要求，分析题目中的关键信息，然后有针对性地解答问题。

- 逻辑清晰：解答题需要展现出逻辑清晰的思维过程，考生需要严谨地分析问题，逐步展开解答，确保思路清晰、结构合理。

- 检查答案：在完成所有题目后，考生需要留出一定时间仔细检查答案，确保没有计算错误或逻辑错误，提高答案的准确性。

5. 实例分析- 通过具体的例题分析，考生可以更好地理解物理考试的解题思路和方法，同时也可以更好地掌握解题技巧和应用能力。

综上所述，A Level物理考试是一项综合性强、内容广泛的考试，考生在备考过程中需要注重对基本原理的理解、解题能力的训练，同时也要注重解题技巧和答题方法的掌握。

只有全面提升自己的物理素养，才能在考试中取得更好的成绩。

Alevel physics 总结(A1)

MeasurementBase quantities and their units; mass (kg), length (m), time (s), current (A), temperature (K), amount of substance (mol): Derived units as products or quotients of the base units:Prefixes and their symbols to indicate decimal sub-multiples or multiples of both base and derived units:Estimates of physical quantities:When making an estimate, it is only reasonable to give the figure to 1 or at most 2 significant figures since an estimate is not very precise.Occasionally, students are asked to estimate the area under a graph. The usual method of counting squares within the enclosed area is used. (eg. Topic 3 (Dynamics), N94P2Q1c)Often, when making an estimate, a formula anda simple calculation may be involved.EXAMPLE 1:Estimate the average running speed of a typical 17-year-old‟s 2.4-km run.velocity = distance / time = 2400 / (12.5 x 60) = 3.2 ≈3 ms-1EXAMPLE 2:Which estimate is realistic?Distinction between systematic errors (including zero errors) and random errors and between precision and accuracy:Random error: is the type of error which causes readings to scatter about the true value.Systematic error: is the type of error which causes readings to deviate in one direction from the true value.Precision: refers to the degree of agreement (scatter, spread) of repeated measurements of the same quantity. {NB: regardless of whether or not they are correct.}Accuracy: refers to the degree of agreement between the result of a measurement and the true value of the quantity.Assess the uncertainty in a derived quantity by simple addition of actual, fractional or percentage uncertainties (a rigorous statistical treatment is not required).For a quantity x = (2.0 ± 0.1) mm,Actual/ Absolute uncertainty, Δ x = ± 0.1 mmFractional uncertainty, Δxx = 0.05100% = 5 % Percentage uncertainty, ΔxxIf p = (2x + y) / 3 or p = (2x - y) / 3 , Δp = (2Δx + Δy) / 3If r = 2xy3 or r = 2x / y3, Δr / r = Δx / x + 3Δy / yActual error must be recorded to only 1 significant figure, &The number of decimal places a calculated quantity should have is determined by its actual error.For eg, suppose g has been initially calculated to be 9.80645 ms-2& Δg has been initially calculated to be 0.04848 ms-2. The final value of Δg must be recorded as 0.05 ms-2 {1 sf }, and the appropriate recording of g is (9.81 ± 0.05) ms-2.Distinction between scalar and vector quantities:Representation of vector as two perpendicular components:In the diagram below, XY represents a flat kite of weight 4.0 N. At a certain instant, X Y is inclined at 30° to the horizontal and the wind exerts a steady force of 6.0 N at right angles to XY so that the kite flies freely.KinematicsDisplacement, speed, velocity and acceleration:Distance: Total length covered irrespective of the direction of motion.Displacement: Distance moved in a certain direction.Speed: Distance travelled per unit time.Velocity: is defined as the rate of change of displacement, or, displacement per unit time{NOT: displacement over time, nor, displacement per second, nor, rate of change of displacement per unit time}Acceleration: is defined as the rate of change of velocity.Using graphs to find displacement, velocity and acceleration: •The area under a velocity-time graph is the change in displacement.•The gradient of a displacement-time graph is the {instantaneous} velocity.•The gradient of a velocity-time graph is the acceleration.The 'SUVAT' Equations of MotionThe most important word for this chapter is SUVAT, which stands for: •S (displacement),•U (initial velocity),•V (final velocity),• A (acceleration) and•T (time)of a particle that is in motion.Below is a list of the equations you MUST memorise, even if they are in the formula book, memorise them anyway, to ensure you can implement them quickly.1. v = u +at derived from definition of acceleration: a = (v – u) / t2. s = ½ (u + v) t derived from the area under the v-t graph3. v2 = u2 + 2as derived from equations (1) and (2)4. s = ut + ½at2derived from equations (1) and (2)These equations apply only if the motion takes place along a straight line and the acceleration is constant; {hence, for eg., air resistance must be negligible.}Motion of bodies falling in a uniform gravitational field with air resistance:Consider a body moving in a uniform gravitational field under 2 different conditions:Without Air Resistance:Assuming negligible air resistance, whether the body is moving up, or at the highest point or moving down, the weight of the body, W, is the only force acting on it, causing it to experience a constant acceleration. Thus, the gradient of the v-t graph is constant throughout its rise and fall. The body is said to undergo free fall.With Air Resistance:If air resistance is NOT negligible and if it is projected upwards with the same initial velocity, as the body moves upwards, both air resistance and weight act downwards. Thus its speed will decrease at a rate greater than 9.81 ms-2 . This causes the time taken to reach its maximum height reached to be lower than in the case with no air resistance. The max height reached is also reduced.At the highest point, the body is momentarily at rest; air resistance becomes zero and hence the only force acting on it is the weight. The acceleration is thus 9.81 ms-2 at this point.As a body falls, air resistance opposes its weight. The downward acceleration is thus less than 9.81 ms-2. As air resistance increases with speed, it eventually equals its weight (but in opposite direction). From then there will be no resultant force acting on the body and it will fall with a constant speed, called the terminal velocity.Equations for the horizontal and vertical motion:Parabolic Motion: tan θ = v y / v xθ: direction of tangential velocity {NOT: tan θ = s y / s x }DynamicsNewton's laws of motion:Newton's First LawEvery body continues in a state of rest or uniform motion in a straight line unless a net (external) force acts on it.Newton's Second LawThe rate of change of momentum of a body is directly proportional to the net force acting on the body, and the momentum change takes place in the direction of the net force.Newton's Third LawWhen object X exerts a force on object Y, object Y exerts a force of the same type that is equal in magnitude and opposite in direction on object X.The two forces ALWAYS act on different objects and they form anaction-reaction pair.Linear momentum and its conservation:Mass: is a measure of the amount of matter in a body, & is the property of a body which resists change in motion.Weight: is the force of gravitational attraction (exerted by the Earth) on a body. Linear momentum: of a body is defined as the product of its mass and velocity ie p = m vImpulse of a force (I):is defined as the product of the force and the time Δt during which it actsie I = F x Δt {for force which is const over the duration Δt}For a variable force, the impulse I = Area under the F-t graph { ∫Fdt; may need to “count squares”}Impulse is equal in magnitude to the change in momentum of the body acted on by the force.Hence the change in momentum of the body is equal in mag to the area under a (net) force-time graph.{Incorrect to define impulse as change in momentum}Force: is defined as the rate of change of momentum, ie F = [ m (v - u) ] / t = ma or F = v dm / dtThe {one} Newton: is defined as the force needed to accelerate a mass of 1 kg by 1 m s-2.Principle of Conservation of Linear Momentum: When objects of a system interact, their total momentum before and after interaction are equal if no net (external) force acts on the system.•The total momentum of an isolated system is constant•m1 u1 + m2 u2 = m1 v1 + m2 v2 if net F = 0 {for all collisions }NB: Total momentum DURING the interaction/collision is also conserved. (Perfectly) elastic collision: Both momentum & kinetic energy of the system are conserved.Inelastic collision: Only momentum is conserved, total kinetic energy is not conserved.Perfectly inelastic collision: Only momentum is conserved, and the particles stick together after collision. (i.e. move with the same velocity.)For all elastic collisions, u1– u2 = v2– v1ie. relative speed of approach = relative speed of separationor, ½ m1u12 + ½ m2u22 = ½ m1v12 + ½ m2v22In inelastic collisions, total energy is conserved but Kinetic Energy may be converted into other forms of energy such as sound and heat energy.ForcesHooke's Law:Within the limit of proportionality, the extension produced in a material is directly proportional to the force/load appliedF = kxForce constant k = force per unit extension (F/x)Elastic potential energy/strain energy = Area under the F-x graph {May need to “count the squares”}For a material that obeys Hooke‟s law,Elastic Potential Energy, E = ½ F x = ½ k x2Forces on Masses in Gravitational Fields:A region of space in which a mass experiences an (attractive) force due to the presence of another mass.Forces on Charge in Electric Fields:A region of space where a charge experiences an (attractive or repulsive) force due to the presence of another charge.Hydrostatic Pressure p = ρgh{or, pressure difference between 2 points separated by a vertical distance ofh }Upthrust: An upward force exerted by a fluid on a submerged or floating object; arises because of the difference in pressure between the upper and lower surfaces of the object.Archimedes' Principle: Upthrust = weight of the fluid displaced by submerged object.ie Upthrust = Vol submerged x ρfluid x gFrictional Forces:•The contact force between two surfaces = (friction2 + normal reaction2)½•The component along the surface of the contact force is called friction •Friction between 2 surfaces always opposes relative motion {or attempted motion}, and•Its value varies up to a maximum value {called the static friction} Viscous Forces:• A force that opposes the motion of an object in a fluid•Only exists when there is (relative) motion•Magnitude of viscous force increases with the speed of the object Centre of Gravity of an object is defined as that pt through which the entire weight of the object may be considered to act.A couple is a pair of forces which tends to produce rotation only.Moment of a Force: The product of the force and the perpendicular distance of its line of action to the pivotTorque of a Couple: The produce of one of the forces of the couple and the perpendicular distance between the lines of action of the forces. (WARNING: NOT an action-reaction pair as they act on the same body.)Conditions for Equilibrium (of an extended object):1. The resultant force acting on it in any direction equals zero2. The resultant moment about any point is zeroIf a mass is acted upon by 3 forces only and remains in equilibrium, then1. The lines of action of the 3 forces must pass through a common point2. When a vector diagram of the three forces is drawn, the forces will forma closed triangle (vector triangle), with the 3 vectors pointing in thesame orientation around the triangle.Principle of Moments: For a body to be in equilibrium, the sum of all the anticlockwise moments about any point must be equal to the sum of all the clockwise moments about that same point.Work, Energy and PowerWork Done by a force is defined as the product of the force and displacement (of its point of application) in the direction of the forceW = F s cos θNegative work is said to be done by F if x or its compo. is anti-parallel to FIf a variable force F produces a displacement in the direction of F, the work done is determined from the area under F-x graph. {May need to find area by “counting the squares”. }By Principle of Conservation of Energy,Work Done on a system = KE gain + GPE gain + Work done against friction} Consider a rigid object of mass m that is initially at rest. To accelerate it uniformly to a speed v, a constant net force F is exerted on it, parallel to its motion over a displacement s.Since F is constant, acceleration is constant,Therefore, using the equation:v2 = u2 +2as,as = 12 (v2 - u2)Since kinetic energy is equal to the work done on the mass to bring it from rest to a speed v,The kinetic energy, E K = Work done by the force F= Fs= mas= ½ m (v2 - u2)Gravitational potential energy: this arises in a system of masses where there are attractive gravitational forces between them. The gravitational potential energy of an object is the energy it possesses by virtue of its position in a gravitational field.Elastic potential energy: this arises in a system of atoms where there are either attractive or repulsive short-range inter-atomic forces between them. Electric potential energy: this arises in a system of charges where there are either attractive or repulsive electric forces between them.The potential energy, U, of a body in a force field {whether gravitational or electric field} is related to the force F it experiences by:F = - dU / dx.Consider an object of mass m being lifted vertically by a force F, without acceleration, from a certain height h1 to a height h2. Since the object moves up at a constant speed, F is equal to mg.The change in potential energy of the mass = Work done by the force F= F s= F h= m g hEfficiency: The ratio of (useful) output energy of a machine to the input energy.ie = Useful Output Energyx100% =Useful Output Powerx100% Input Energy Input PowerPower {instantaneous} is defined as the work done per unit time.P = Total Work Done=W Total Time tSince work done W = F x s,P = F x s= Fv t•for object moving at const speed: F = Total resistive force {equilibrium condition}•for object beginning to accelerate: F = Total resistive force + ma Thermal PhysicsInternal Energy: is the sum of the kinetic energy of the molecules due to its random motion & the potential energy of the molecules due to the intermolecular forces.Internal energy is determined by the values of the current state and is independent of how the state is arrived at. Thus if a system undergoes a series of changes from one state A to another state B, its change in internal energy is the same, regardless of which path {the changes in the p & V} it has taken to get from A to B.Since Kinetic Energy proportional to temp, and internal energy of the system = sum of its Kinetic Energy and Potential Energy, a rise in temperature will cause a rise in Kinetic Energy and thus an increase in internal energy.If two bodies are in thermal equilibrium, there is no net flow of heat energy between them and they have the same temperature. {NB: this does not imply they must have the same internal energy as internal energy depends also on the number of molecules in the 2 bodies, which is unknown here}Thermodynamic (Kelvin) scale of temperature: theoretical scale that is independent of the properties of any particular substance.An absolute scale of temp is a temp scale which does not depend on the property of any particular substance (ie the thermodynamic scale)Absolute zero: Temperature at which all substances have a minimum internal energy {NOT: zero internal energy.}T/K = T/°C + 273.15, by definition of the Celsius scale.Specific heat capacity is defined as the amount of heat energy needed to produce unit temperature change {NOT: by 1 K} for unit mass {NOT: 1 kg} of a substance, without causing a change in state.c = Q / mΔTSpecific latent heat of vaporisation is defined as the amount of heat energy needed to change unit mass of a substance from liquid phase to gaseous phase without a change of temperature.Specific latent heat of fusion is defined as the amount of heat energy needed to change unit mass of a substance from solid phase to liquid phase without a change of temperatureL = Q / m {for both cases of vaporisation & melting}The specific latent heat of vaporisation is greater than the specific latent heat of fusion for a given substance because•During vaporisation, there is a greater increase in volume than in fusion,•Thus more work is done against atmospheric pressure during vaporisation,•The increase in vol also means the INCREASE IN THE (MOLECULAR) POTENTIAL ENERGY, & hence, internal energy, during vaporisationmore than that during melting,•Hence by 1st Law of Thermodynamics, heat supplied during vaporisation more than that during melting;•hence l v > l f{since Q = ml = ΔU - W}.Note:1. the use of comparative terms: greater, more, and>2. the increase in internal energy is due to an increase in the PE, NOT KEof molecules3. the system here is NOT to be considered as an ideal gas system Similarly, you need to explain why, when a liq is boiling, thermal energy is being supplied, and yet, the temp of the liq does not change.First Law of Thermodynamics:The increase in internal energy of a system is equal to the sum of the heat supplied to the system and the work done on the system.ΔU = W + Q ΔU: Increase in internal energy of the systemQ: Heat supplied to the systemW: work done on the system{Need to recall the sign convention for all 3 terms}Work is done by a gas when it expands; work is done on a gas when it is compressed.W = area under pressure - volume graph.For constant pressure {isobaric process}, Work done = pressure x ΔVolumeIsothermal process: a process where T = const {ΔU = 0 for ideal gas}ΔU for a cycle = 0 {since U ∝T, & ΔT = 0 for a cycle }Equation of state for an ideal gas:p V = n R T, where T is in Kelvin {NOT: °C}, n: no. of moles.p V = N k T, where N: no. of molecules, k:Boltzmann constIdeal Gas: a gas which obeys the ideal gas equation pV = nRT FOR ALL VALUES OF P, V & TAvogadro constant: defined as the number of atoms in 12g of carbon-12. It is thus the number of particles (atoms or molecules) in one mole of substance.For an ideal gas, internal energy U = Sum of the KE of the molecules only {since PE = 0 for ideal gas}U = N x½ m <c2> = N x (3/2)kT {for monatomic gas}•U depends on T and number of molecules N•U ∝T for a given number of moleculesAve KE of a molecule, ½ m <c2> ∝T { T in K: not °C }Wave MotionDisplacement (y): Position of an oscillating particle from its equilibrium position.Amplitude (y0 or A): The maximum magnitude of the displacement of an oscillating particle from its equilibrium position.Period (T): Time taken for a particle to undergo one complete cycle of oscillation.Frequency (f): Number of oscillations performed by a particle per unit time.Wavelength (λ): For a progressive wave, it is the distance between any two successive particles that are in phase, e.g. it is the distance between 2 consecutive crests or 2 troughs.Wave speed (v): The speed at which the waveform travels in the direction of the propagation of the wave.Wave front: A line or surface joining points which are at the same state of oscillation, i.e. in phase, e.g. a line joining crest to crest in a wave.Ray: The path taken by the wave. This is used to indicate the direction of wave propagation. Rays are always at right angles to the wave fronts (i.e. wave fronts are always perpendicular to the direction of propagation).From the definition of speed, Speed = Distance / TimeA wave travels a distance of one wavelength, λ, in a time interval of one period, T.The frequency, f, of a wave is equal to 1 / TTherefore, speed, v = λ / T = (1 / T)λ = fλv = fλExample 1:A wave travelling in the positive x direction is showed inthe figure. Find the amplitude, wavelength, period, andspeed of the wave if it has a frequency of 8.0 Hz.Amplitude (A) = 0.15 mWavelength (λ) = 0.40 mPeriod (T) = 1f = 18.0 ≈ 0.125 sSpeed (v) =fλ = 8.0 x 0.40 = 3.20 m s-1A wave which results in a net transfer of energy from oneplace to another is known as a progressive wave.Intensity {of a wave}: is defined as the rate of energy flow per unit time {power} per unit cross-sectional area perpendicular to the direction of wavepropagation.Intensity = Power / Area = Energy / (Time x Area)For a point source (which would emit spherical wavefronts),Intensity = (½mω2x o2) / (t x 4πr2) where x0: amplitude & r: distance from thepoint source.Therefore, I ∝x o2 / r2 (Pt Source)For all wave sources, I ∝(Amplitude)2Transverse wave:A wave in which the oscillations of the wave particles {NOT: movement} areperpendicular to the direction of the propagation of the wave.Longitudinal wave:A wave in which the oscillations of the wave particles are parallel to the direction of the propagation of the wave.Polarisation is said to occur when oscillations are in one direction in a plane, {NOT just “in one direction”} normal to the direction of propagation.Example 2:。

ALEVEL物理AUnit复习资料之

Section 6: OscillationsRevision spread1 : Simple harmonic motionCheckpoints : (1)recall that the condition for simple harmonic motion is F=-kxIdentify situations in which simple harmonic motion will occur.(2) recognize and use the expressions a=-ω2x, a=-Aω2xcosωt,v=-Aωsinωt,x=A cosωt,and T=1/f=2π/ωas applied to asimple harmonic oscillator.(3) obtain a displacement-time graph for an oscillating objectand recognize that the gradient at a point gives the velocity atthat point.（201306-1）A mass is bouncing on the end of a vertical spring. Its motion will be simple harmonic if the springA .can store energy.B .has elasticity.C .is hung vertically.D .obeys Hooke’s law.（201206-4）Which of the following is not an example of simple harmonic motion?A A car bouncing on its suspension system.B A child jumping on a trampoline.C A person bouncing on the end of a bungee cord.D A swinging pendulum in a grandfather clock.201301（201201-13）(a) Define simple harmonic motion(b) The graph shows the variation in water level displacement with time for the water in a harbour. The water level displacement varies with simple harmonic motion.(i) Use the graph to calculate the amplitude and the time period of the variation in the water level displacement.(ii) Show that the maximum rate of change of water level displacement is about 0.6 m hour–1.(iii) On the axis below sketch how the rate of change of water level displacement varies with time for the interval 0–30 hours. The variation in water level displacement with time has been drawn for you. You need not add any numerical values to the y-axis.Revision spread2 :Energy and damping in SHMCheckpoints : (1)Recall that the total energy of an undamped SHM system remains constant and recognize ad use expressions for the totalenergy of an oscillator.(2) Distinguish between free and damped oscillations(201306r-7) An object is hung from a vertical spring and undergoes undamped simple harmonic motion. It is correct to say that there are no changes in theA .elastic potential energy of the oscillating system.B .gravitational potential energy of the oscillating system.C .kinetic energy of the oscillating system.D .total energy of the oscillating system.(201306-9)For an object undergoing simple harmonic motion select the graph that represents the variation of kinetic energy with displacement.(201306-10) For an object undergoing simple harmonic motion select the graph that represents the variation of the total energy with displacement.Revision spread3 :Forced oscillations and resonance .Checkpoints : (1)Distinguish between free, damped and forced oscillations .(2) Investigate and recall how the amplitude of a forced oscillationchanges at and around the natural frequency of a system .Describe qualitatively how damping affects resonance .(3)Explain how damping and the plastic deformation of ductilematerials reduce the amplitude of oscillation .(201306-8) A car is travelling over a rough road surface. At low speed the ride is very bumpy with the car and its occupants suffering large amplitude vertical oscillations. However, when the car is driven at a higher speed the ride gets smoother. This is because at the higher speedA .the car leaves the ground and misses the bumps.B .the car crushes the bumps and makes the road smoother.C .there is a greater amount of damping in the car’s suspension.D .the car’s suspension oscillates at a greater frequency than its natural frequency (201206-7) When one system is driven into oscillation by another, the driven system A. exhibits resonance. B. has a large increase in amplitude.C. vibrates at its natural frequency.D. vibrates at the driver frequency. (201301-4)New buildings in earthquake zones are often designed to be earthquake resistant .Such buildings incorporate mechanisms to reduce the transfer of kinetic energy from the ground to the building. Which of the following would be the most important property of a material used in such a mechanism ?A.densityB. ductilityC. stiffnessD.strength(201306-13) The diagram shows a number of pendulums hanging from a single thread. Pendulum X has a heavy lead sphere as the bob and the others have low mass bobs. When X is set into motion energy is transferred to the others which all begin to oscillate.After a short time C is observed tohave the largest amplitude ofoscillation.(a) Explain why pendulum C has the largest amplitude of oscillation.(b)For an efficient energy transfer pendulum C must be at rest when pendulum X has its maximum kinetic energy. The graph below shows how the displacement of pendulum X varies with time.Mark a point P on this graph showing an instant when pendulum X has a maximum kinetic energy, and add a curve to show how the displacement of pendulum C varies over the same time interval.(201306r-18)A baby-bouncer is a light harness, into which a baby can be placed, suspended by a vertical spring.The height of the baby-bouncer is adjusted so that the baby’s feet are a few centimetres above the floor when the baby is in equilibrium in the harness. If the baby is then displaced downwards and released, the system oscillates vertically with simple harmonic motion. It is stated in a textbook that “a mass-spring system that obeys Hooke’s law will lead to simple harmonic motion when the mass is displaced.”*(a) Exp lain why a system consisting of a mass and a spring that obeys Hooke’s law may be set into simple harmonic motion.(b) The acceleration experienced by a baby of mass 8.2 kg is 0.49 m s-2when the displacement from the equilibrium position is 3.0 cm.Show that the period of vertical oscillations for this baby is about 1.6 s.(c) The amplitude of the oscillations quickly decreases, so the baby has to keep kicking on the floor to maintain them.(i) State the name given to oscillations that die away quickly.(ii) State the name that is given to oscillations such as those that are kept going by the baby kicking on the floor.(iii) If the baby kicks on the floor at a certain frequency, the amplitude of the bounces can be made to increase to a maximum.Name this effect and calculate the frequency at which it occurs(d) The baby is replaced by a baby of less mass. This baby also kicks to produce maximum amplitude of oscillation. Without further calculation, explain how the frequency at which the baby must kick compares to that for the larger mass baby. (201206-17) The photograph shows a nodding tiger toy. The tiger is placed on a car’s dashboard and its head nods up and down as the car is driven along a rough road surface. It is n oticed that at a particular speed the tiger’s head vibrates with maximum amplitude.(a) (i) What is the name of this phenomenon?(ii) Describe the conditions necessary for thisphenomenon to occur.(b) (i) The graph shows the variation of accelera tion with time for the tiger’s head. Using values from the graph calculate the amplitude of oscillation of the tiger’s head.(ii) Sketch a graph of the head’s displacement against time over the same time interval on the axes below.(201201-14)*When a tuning fork is struck with a rubber hammer, a pure sound of fixed frequency is produced. The photograph shows a tuning fork connected to a wooden sounding box..The sounding box amplifies the sound produced when the tuning fork is struck ..The sound lasts for a shorter time than if the tuning fork were t be struck identically but without the sounding box.Explain these observations.。

A-LEVEL物理A2Unit5复习资料4

Unit 5 physics from creation to collapseSection 4 thermal energyRevision spread :1.internal energyCheckpoints :(1) Explain the concept of internal energy as the random distribution of potential and kinetic energy among molecules.(2) Explain the concept of absolute zero and how the averagekinetic energy of molecules is related to the absolutetemperature .(3) recognize and use the expression ΔE=mcΔθ.(201306r-10)The absolute temperature scale is a theoretical scale proposed by Lord Kelvin.On this scale, zero is the temperature at whichA .all gases become liquids.B .an ideal gas would exert no pressure.C .the Celsius temperature is −373 °C.D .water freezes.(201306-12) The heating element of an electric shower has a power of 6.0kW(a) The shower is operated from a 230 V mains supply. Calculate the resistanceof the heating element.(b)Water enters the shower at a temperature of 7.5 °C.Calculate the water flow rate required to give an output temperature of 37.5 °C. specific heat capacity of water =4200J kg–1K–1Revision spread :2. gas laws and kinetic theoryCheckpoints :(1)recognize and use the expression 1/2m<c2>=3/2 kT(2)use pV=NkT as the equation of state for an ideal gas . (201306-2) When energy is supplied to a substance, changes in the average molecular kinetic energy (E k) and the average molecular potential energy (E p) can occur.When energy is supplied to an ideal gasA .both E k and E p increase.B .E k may increase.C .E p may increase.D .E k increases but E p decreases.(201306-7) Air is a mixture of mostly nitrogen and oxygen molecules. The mass of an oxygen molecule is slightly greater than the mass of a nitrogen molecule.On average, in a sample of air at a given temperatureA .the nitrogen and oxygen molecules have the same speed.B .the nitrogen molecules are travelling more slowly than the oxygen molecules.C .the oxygen molecules are travelling more slowly than the nitrogen molecules.D .the molecules have relative speeds that depend upon the amount of each gas present.(201206-1) A sealed gas jar contains a mixture of different gases. At a given temperature, the mean kinetic energy of the molecules of each gasA .depends upon how much of each gas is present.B .is greater for the gas with less massive molecules.C .is greater for the gas with more massive molecules.D. is the same for each gas in the mixture.(201306r-1) At night the Earth’s surface cools down as energy is radiated away into space. Most of the energy is radiated away asA .infrared radiation.B .microwaves.C .ultraviolet radiation.D .visible light.(201306r-15) Hot air ballooning is one way to explore the landscape. Air in a balloon is heated from underneath by a set of burners and the balloon starts to rise.(a) Explain why heating the air causes the balloon to rise.(b)In1991, Per Lindstrand andRichard Branson become the firstpeople to cross the Pacific in a hot air balloon.With a volume of 7.4 × 104 m3 the balloon was, at the time, the largest ever built. Calculate the energy supplied by the burners to heat the air from 20.0 °C to 35.0 °C. average density of air in the balloon = 1.20 kg m–3specific heat capacity of air = 1010 J kg−1 K−1(c) The first balloons used were filled with hydrogen and sealed to keep the volume constant. As the balloon rose there would be changes in the pressure of the hydrogen due to the temperature changes of the atmosphere.(i) Calculate the new pressure exerted by the hydrogen if the temperature changed from 20.0 °C to −5.0 °C, as the balloon rose from ground level.pressure exerted by the hydrogen in the balloon at ground level = 1.01 × 105 Pa (ii) State two assumptions that you must make to calculate this change.*(iii) By considering the motion of molecules in the gas, explain why the pressure exerted by the gas decreases as it cools.(201306-16) A student uses the apparatus shown to investigate the relationship between pressure and volume of a gas.Air is trapped in a glass tube of uniform cross-sectional area. As the pressure of the trapped air is increased, the length of trapped air decreases. The student collects data and plots the following graph.(a)State the variables that should be controlled in this investigation.(b) Theory suggests that, for the air trapped in the tube, the pressure p is inversely proportional to the volume V. Use the graph to show that this relationship is correct. State an assumption that you are making.(c) On the day that the investigation was carried out, the temperature in the laboratory was 20°C. Calculate the number of air molecules trapped in the tube. cross-sectional area o f tube =7.5×10–5m2(d)State how the graph would change if(i) the air molecules in the tube were replaced by the same number of molecules of hydrogen gas.(ii) the temperature of the laboratory was substantially higher.(201206-12)Two metal spheres of the same size are heated to a temperature of 100 °C in a water bath. One of the spheres is made of lead and the other of steel. The spheres are then placed onto a sheet of paraffin wax as shown. Paraffin wax melts at 55 °C.(a) The steel sphere melts through the wax sheet and drops to the floor. The temperature of the steel sphere when it reaches the floor is 53 °C.Calculate the thermal energy lost by the steel sphere from the time when it was removed from the water bath.(b) The lead sphere is only able to partially melt the wax, so does not drop to the floor. Explain this observation.(201206-14)A magazine article states that an inflated balloon contains about two hundred billion trillion (2 × 1023) air molecules.(a) Taking the balloon to be a sphere of volume 8.2 ×10–3m3in a room at a temperature of 22 °C, show that this figure for the number of molecules is correct. pressure of air in balloon = 1.1 × 105Pa*(b) The article also states that the internal energy of the air in the balloon could become zero if the temperature of the gas became low enough.Explain what is meant by the internal energy of the air and discuss whether the statement is correct(201203-15 )A washing machine uses 15 litres of water in a hot-wash cycle in which the machine is set to wash at 60°C.1.0 litre of water has a mass of 1.0 kgspecific heat capacity of water = 4200 J kg–1 K–1(a)On a particular day the inlet temperature of the water is 15°C. Show that the energy that must be supplied in order to bring the water to the correct temperature is about 3 MJ(b) (i) The power of the heater is 2.5 kW. Calculate the minimum time it takes for the water to be brought to the correct temperature.(ii) State an assumption you made in your calculation.(c) The washing machine is connected to a 230 V supply. What current is drawn from the supply by the heater?。

A-Level物理知识点梳理系列(一)

A-Level物理知识点梳理系列（一）物理量及单位 ( physical quantities and units)A-level物理AS阶段涵盖了物理量、测量、运动学、力学、功与能量、物质与材料学、波、电学以及核物理等九大版块。

本次知识梳理将对各个板块所涵盖的知识点、重要公式以及相关的典型真题进行精讲精练。

本期将对物理量 ( physical quantities and units) 进行专题讲解，这一部分是AS物理的开篇内容，与其他章节比相对简单，但又是学好后续章节的基础。

CIE物理paper1的前两小题及paper2的第一题一般会考察此章节内容。

一、矢量与标量Vectors and scalarsscalar: physical quantity that has magnitude only.vector: physical quantity that has magnitude and direction.区分矢量与标量的唯一标准为所描述的物理量是否包含方向(direction)这一要素. 包含方向要素则为矢量(vector)，如位移(displacement)、速度(velocity)等；若仅用大小(magnitude) 即可描述，则该物理量为标量，如温度(temperature),功率(power)等。

真题解析S 041 Which pair contains one vector and one scalar quantity?A displacement : accelerationB force : kinetic energyC momentum : velocityD power : speed此题为04年春季paper1的第一小题。

alevel物理知识点盘点

alevel物理知识点盘点A-level物理知识点盘点A-level物理是一门高中阶段的课程，涵盖了许多重要的物理知识点。

在这篇文章中，我们将对A-level物理课程中的一些关键知识点进行盘点，以帮助学生更好地理解和掌握这门学科。

首先，让我们从力学这一重要领域开始。

在A-level物理中，学生将学习力学的基本原理，包括牛顿三定律、动量和能量守恒定律等。

这些概念是力学研究的基础，是理解物体运动和相互作用的关键。

另一个重要的知识点是电磁学。

在A-level物理中，学生将学习关于电场、磁场和电磁感应等概念。

他们将了解电荷之间的相互作用、电场的产生和性质，以及磁场对电荷的影响。

这些知识对于理解电磁现象和应用有着重要的意义。

热学是A-level物理课程中的另一个重要领域。

学生将学习热力学的基本原理，包括热量、温度和热传导等概念。

他们将了解热力学定律，热量的传递方式以及热力学循环的原理。

这些知识对于理解能量转化和热力学系统的行为至关重要。

此外，A-level物理课程还涵盖了光学和现代物理学的内容。

学生将学习光的波动性和粒子性，以及光的折射、反射和干涉等现象。

他们还将了解相对论和量子物理等现代物理学的重要概念，包括光速不变原理和量子力学的基本原理。

总的来说，A-level物理课程涵盖了许多重要的物理知识点，包括力学、电磁学、热学、光学和现代物理学等领域。

通过学习这些知识点，学生将能够更深入地理解物理学的基本原理和应用，为未来的学习和研究奠定坚实的基础。

希望本文的知识点盘点能够帮助学生更好地理解A-level物理课程的重点内容，取得更好的学习成绩。