Kinematics
| m18 qp42 Q1(a) m19 qp42 Q1(a) |
| Define acceleration |
| Rate of change of speed change of speed / time \[ a = \frac{\Delta v}{\Delta t} \] |
| m19 qp42 Q3(a) |
| State three ways in which a force may change the motion of the object |
| • Accelerate or increase speed | Decelerate or decrease speed | Change speed • Change direction • Causes rotation |
Dynamics
| m18 qp42 Q2(a) |
| Define moment of a force |
| The moment of a force about a pivot is equal to the magnitude of the force multiplied by the perpendicular distance from the pivot to the line of action of the force \[ \text{moment} = r_\perp \times F \] |
| s23 qp42 Q1(b)ii |
| Explain in terms of forces, the changes in motion which occur from when the parachutist leaves the hot-air ballon until point A |
| (initially there is acceleration due to) weight OR gravitational force OR unbalanced force/resultant force/downward force (then) air resistance increases as speed or velocity increases (as air resistance increases) resultant force downwards decreases OR acceleration decreases constant speed when air resistance = weight/gravitational force |
| m23 qp42 Q2(b) |
| The containers with the greatest mass are loaded near the bottom of the ship. State and explain the effect on the stability of the ship of loading the containers in this way. 轮船装货为什么装在底部 |
| the centre of gravity is lower and (so) the ship is more stable 各一分； 只要是稳定性，都是讨论重心centre of gravity高低。 |
| s23 qp43 Q2(a) |
| Define pressure. |
| (pressure is) force per unit area |
Work and Energy
| w18 qp42 Q1(a) m23 qp42 Q3(a) |
| State what is meant by the principle of conservation of energy |
| Energy cannot be created or destroyed OR energy can only be transferred from one form to another OR total energy remains constant 有两分的话，再加以下的一句话 energy can be transferred / transformed (between energy stores) |
Resources of Energy
| m19 qp42 Q1(a) |
| State one advantage and one disadvantage of using a wind turbine as a source of electrical energy. |
| Advantage: No fossil fuel used No fuel costs No pollution of air / water No polluting gases is a renewableenergy source doesn’t contribute to global warming / greenhouse effect Disadvantage: Wind not always blowing causes noise pollution causes visual pollution is danger to wildlife is expensive to build |
| w23 qp42 Q2(c) |
| Suggest why using a clothesline to dry clothes in the open air is better for the environment than using an electric tumble dryer. |
| uses (solar / wind) energy which is renewable energy (re)sources not used to generate electricity greenhouse gases not produced does not use (fossil) fuels since no electricity has been used |
| w23 qp42 Q8(c) i |
| Describe how thermal energy from nuclear reactions is used to generate electricity in a power station. 核能发电的流程 |
| (thermal energy) used to heat / boil (cold) water OR make steam steam is at high pressure steam drives a turbine turbine (connected to and) drives a generator turbine moves a coil in a magnetic field 记住本质就是烧开水—>驱动涡轮—>驱动发电机中的线圈，切割磁场线进行发电  |
| w23 qp42 Q8(c) ii |
| State one advantage and one disadvantage of using nuclear fuels in a power station instead of using fossil fuels. |
| advantage – any one from: (much) small(er) amount of fuel needed (to produce same amount of energy) no greenhouse gases produced OR low carbon dioxide emissions no air pollution (when operating normally) disadvantage – any one from danger if any leak of radiation produces hazardous / dangerous / toxic waste OR difficulty of storage of used radioactive material OR nuclear waste must be stored for a long time expensive to build or decommission nuclear power plant or store nuclear waste |
| m23 qp42 Q3(c) |
| Radiation from the Sun is the main source of energy for most of our energy resources. State two energy resources that are NOT due to radiation from the Sun. |
| 非来自于太阳的能源： geothermal nuclear tidal 衍生题目 来自于太阳辐射的能源： fossil fuels hydroelectricity (hydroelectric dams) solar energy wind energy |
| State and explain whether each of the following methods of electrical power generation is renewable. |
| (nuclear) fuel is used up, so nuclear/fossil fuel power plant is NON-renewable; nothing is used up, so wind/tidal/geothermal/solar/hydroelectric power plant is renewable. 或者说，wind/tides/hydrocycle/solar energy will always continue. |
Thermal
| w18 qp41 Q1(a) |
| State three factors that determine the rate of evaporation of water. |
| • Temperature (of liquid / water) • Surface area (of liquid / water) • Wind blowing / movement of air (over surface) • Temperature of surroundings • Draught / Humidity (of surrounding air) |
| m19 qp42 Q7(b) |
| Explain, in terms of the forces between their molecules, why gases expand more than solids when they undergo the same rise in temperature. |
| (Neighbouring) molecules of solid have (strong) forces of attraction between them | Gas molecules have no / weak forces of attraction between them Easier to increase separation of gas molecules (than solid molecules) (gas expands more easily so) gas molecules move farther apart |
| m22 qp42 Q3(c) |
| Explain, in terms of molecules, how sweating helps to cool your body on a hot day. |
| • (thermal) energy in the skin/body transferred to (molecules of) sweat • These molecules (have enough KE to) escape from the skin/become water vapour • Leaving behind molecules with lower energy • Which leaves the skin/body at a lower temperature |
| s23 qp42 Q4 (b)ii |
| Explain what is meant by the term absolute zero. Refer to particles in your answers |
| (temperature at which) particles have least EK/kinetic energy lowest possible temperature |
| m23 qp42 Q4(a) |
| Thermal energy is transferred through the metal pan by conduction. State and explain the TWO ways that thermal energy is conducted in a metal |
| delocalised / free / mobile electrons move through metal OR electrons collide with distant particles OR electrons carry energy through the metal lattice vibrations transfer energy to neighbouring particles OR particles vibrate and cause nearby / adjacent particles to vibrate OR vibrating particles collide with particles transferring energy 金属的导热性除了常规的晶格振动互相传递之外，还多一个离域电子的移动，因此金属比其他固体的导热性好； |
| s23 qp43 Q3 b(ii) |
| Define specifc heat capacity |
| ver1: energy required to raise (1kg/) unit mass by (1°C/1K/1 kelvin/)unit temperature ver2: thermal energy per unit mass per unit temperature change. |
| s23 qp43 Q3 b(ii) |
| Define heat capacity for an object. |
| 热容，不是比热容。 energy required to raise the temperature by 1°C/1K/1 kelvin. 抬升、改变物体1摄氏度所需要吸收/改变的能量。 热容=比热*质量 |
Matters
| s18 qp42 Q4(b) |
| Describe the motion of the atoms in a solid |
| 固体： (solids) particles vibrate (solids) particles in fixed/close positions 如果此题变成气体： (gases) particles move freely (gases) particles randomly arranged (in container)/wide separation (gas) particles move quickly |
| w23 qp42 Q4 (a)i |
| Explain, in terms of particles, how the air pressure inside the bottle changes as the temperature increases. |
| increase in the (average) KE / speed of air particles more frequent collisions of (air) particles (with bottle) greater change of momentum of gas particles, hence larger forces during collision more forceful collisions of (air) particles (with bottle) greater force per unit area gives greater pressure volume unchanged and so pressure increases |
| m23 qp42 Q4(b) i |
| The water boils and leaves the liquid as a gas. Explain, in terms of forces and distances between particles, why the gas occupies a much greater volume than it does as a liquid. |
| (attractive) forces (between particles are much) greater in liquids (than in gases) particles in gases are (much) further apart (than in liquids) |
| Define evaporation. |
| the escape of molecules/particles from the surface of the liquid into gaseous state. |
| m23 qp42 Q4(b) ii |
| State two ways in which boiling differs from evaporation |
| occurs at a fixed temperature (boiling point) takes place throughout the liquid |
Waves
| w18 qp41 Q8(a) |
| Explain what is meant by the term longitudinal wave. |
| Particles / molecules / water / medium vibrate Vibration is in the direction travel of the wave Has compressions and rarefactions Sanjin’s Version The direction of vibration of the particles in the longitudinal wave is the same as (parallel to) the direction travel of the wave, hence causing compressions and rarefactiobns |
| w23 qp42 Q7 (c)ii |
| Suggest why a Bluetooth headset only works well over short distances |
| (radio waves / signal) lose energy / get weaker / lose (signal) strength (passing through walls) owtte |
| m23 qp42 Q6(a) |
| Sound waves have compressions and rarefactions. Explain what is meant by compression and rarefaction. |
| (region where) particles are closer together (than normal) OR (region where) there is a greater pressure (than normal) (region where) particles are further / far apart (than normal) OR (region where) there is a lower pressure (than normal) |
Optics
| w18 qp42 Q5(b)iii |
| State two uses of optical fibres. |
| • to carry (telephone) signals / communications • for medical diagnosis / imaging • specified artistic (display) • specified lighting |
| s23 qp43 Q5a (ii) |
| Give two reasons why these two types of electromagnetic radiation are used in glass optical fibres for high-speed broadband |
| 1. glass optical fibres are transparent to visible light and short wavelength infrared; 2. visible light and shortwavelength infrared can carry high rates of data |
| w18 qp41 Q7(a) m22 qp42 Q5(b)i |
| A laser produces a beam of monochromatic light. State what is meant by the term monochromatic. |
| Light of a single colour / wavelength / frequency |
Electricity
| m19 qp42 Q10(a) |
| The electrical energy produced by a power station is transmitted over long distances at a very high voltage. Explain why a very high voltage is used |
| If voltage is (very) high, current is (very) low , (because the power of A.C. is fixed) (If current is low,) thermal energy generated / power loss is low (If current is low:) thinner / lighter / cheaper transmission cables / cables with less resistance / cheaper pylons can be used /cheaper2 |
| w23 qp42 Q6 (b) |
| Explain why the LED does not light up if the battery is reversed. |
| LED (is a diode, which) only allows current in one direction / has a very high resistance (when direction of current isreversed.) Diode is reverse-biased |
| m23 qp42 Q3(b) i |
| Define the unit kW h 千瓦时的定义 |
| energy transferred in one hour at a rate of transfer(power) of 1 kW 功率为1千瓦的用电器在1小时内产生的能量，数据值为3.6*10^6 焦耳 \[ W = P\cdot t \] |
| m23 qp42 Q7(a) |
| Define potential difference (p.d.). |
| work done per unit charge in passing charge through / across a component 来自于公式 \[ V = \frac{E}{Q} \] 或者说： energy transferred per unit charge from electrical to other forms of energy through a component. 比如： 电荷通过电阻器resistor之后，会发热 电荷通过马达motor之后，会转动，具有动能 电荷通过LED之后，会发光，转化为光能 电荷通过扬声器loudspeaker之后，会发出声音，转化为声能 |
Magnetism
| m23 qp42 Q8(c) |
| State and explain what happens to the coil as it reaches the vertical position |
| (at vertical) the coil stops OR (at vertical) the coil overshoots and comes back OR the coil vibrates (about the vertical) any one from: (as the coil approaches vertical) the turning effect decreases (at vertical) the turning effect is zero (past vertical) the turning effect reverses / changes direction |
| s23 qp42 Q8 (a)i |
| State what is meant by a magnetic field |
| region in which a (magnetic) pole experiences a force 中文解释： 磁场指的是磁极放置于其中会收到力的作用的空间区域； 人话解释： 当一个磁极放置在一个区域中，会收到作用力，那么磁场就必定存在于这个空间之中； |
| s23 qp42 Q8 (a)ii |
| Define the direction of a magnetic field. |
| in the direction of the force on the North pole 一定是磁针或者磁体北极的作用力 |
| m23 qp42 Q8(d) |
| Explain the effects of the split‑ring commutator and the carbon brushes on the action of the motor |
| reverses the current any two from: (brushes) ensure current is maintained / owtte coil rotates continuously / continues to move in the same direction (allows current to change direction) without wires getting tangled/twisted (reverses the current) every half turn / 180 degrees / OR (reverses the current) when the coil is vertical / at right anglesto the magnetic field |
Electromagnetism
| w18 qp42 Q9(b)i |
| The magnet is moved to the left and inserted a small distance into the coil. The galvanometer deflects briefly and shows that there is a current in the coil. Explain why there is a current in the coil |
| magnetic field (lines) cut OR changing magnetic field / flux linkage (in coil) e.m.f. / voltage is induced in the coil |
| w18 qp41 Q10(b)i |
| The primary coil of the transformer is connected to the output voltage of an a.c. generator which supplies an alternating current Explain why there is a voltage between the two terminals of the secondary coil. |
| Alternating / changing magnetic field in primary (coil) Alternating / changing (magnetic) field in core (and in secondary coil) OR (magnetic) field lines / flux link secondary e.m.f / voltage induced (in secondary coil) |
| m22 qp42 Q6(b)iii |
Explain how rotating the coil in Fig. 6.2 continuously causes the galvanometer needle to show an alternating current. |
| (as coil rotates) it cuts magnetic field between the magnets This induces an e.m.f./voltage/p.d. (in the coil) This produces a current in the (coil transferred to the) galvanometer (via the slip rings and carbon brushes) Direction of current flow changes with each 180 degree rotation of coil |
| m22 qp42 Q8(b) |
| Explain the operation of a basic transformer |
| (Primary voltage causes) an alternating current in primary coil produces a changing magnetic field (changing) field induces pd/e.m.f. (in secondary coil) |
Radioactivity
| m18 qp42 Q11(a) |
| To ensure the safety of workers in laboratories where radioactive sources are used, describe how radioactive materials |
| should be stored: should be handled: |
| s23 qp42 Q9(a) |
| State two safety precautions taken when moving, using or storing radioactive sources in a laboratory |
| • limit time of exposure • store sources in lead boxes • keep distance from sources • avoid contact OR use tongs OR wear gloves |
| s18 qp42 Q11(b)i m23 qp42 Q9(a)i |
| State what is meant by nuclear fission. |
| splitting of a nucleus into (2) parts/light(er) nucleus 三分版本回答 large unstable nucleus OR neutrons hit nucleus OR neutrons are released (from nucleus) large nucleus splits (into smaller nuclei) release of energy 三金版本： neutrons hit large nucleus, causing the large nucleus splits into 2 or more smaller nuclei, during which the energy is released. |
| s18 qp42 Q11(b)ii |
| Suggest why a nuclear reactor is surrounded by thick concrete walls. |
| (thick concrete walls) absorb/stop the radiation (and so protect workers) |
| m19 qp42 Q11(a) |
| State two ways in which γ-emission differs from β-emission |
 |
| m22 qp42 Q10(b)i |
| Describe how the americium-241 ionises air. |
| alpha particles emitted (from americium) move close to/hit molecules in the air (between the metal plates) removing electrons (out of the molecules) |
| m22 qp42 Q10(b)ii |
| Suggest and explain two reasons why smoke detectors use an isotope that emits α-particles rather than an isotope that emits γ-radiation. |
| • alpha not penetrating/short range AND alpha (particles) stopped by smoke particles • alpha (particles) more highly ionising (than gamma) AND ionise air more easily • range of alpha particles is short/alpha is not penetrating AND alpha less harmful (to humans) B2 |
| s23 qp42 Q9(b) |
| State how β-decay changes the nucleus of an atom |
| (the nucleus has) one less neutron and one more proton OR one neutron in the nucleus will transform into proton |
| During β-decay, one of the neutrons in the nucleus changes. (i) State what happens to this neutron. (ii) Explain how charge is conserved during this change. |
| (i) neutron becomes proton and electron OR (neutron) becomes proton and β– particle (ii) charge on neutron = 0 charge on proton = +1e AND charge on electron = –1e hence, total charge on products is still 0; charge is conserved. |
Space Physics
| m23 qp42 Q10(c) i |
| Light from a distant galaxy is redshifted. Explain what is meant by redshift |
| wavelength (of light from distant galaxies) increases occurs when galaxies are moving away from Earth |
| s23 qp42 Q10(b) |
| Suggest why countries that are a significant distance from the Equator experience significant temperature variation throughout the year. 为什么离赤道很远的国家，一年之中要经历很大的温度变化 |
| rays from Sun strike the country at different angles through the year OR rays from Sun strike the country for different number of hours per day through the year 由于地球自转的旋转轴影响，导致高纬度国家（北欧）日照时间变动太大；  |
| w23 qp42 Q10(a) |
| Complete the sentences about the life cycle of stars. |
| Protostars are formed from (interstellar clouds of) gas and dust OR (stellar) nebula A protostar becomes a stable star when inward force of gravitational attraction is balanced by outward force due to the high temperature (in the centre of the star) |
后面可以继续补充stars的衰亡过程：
if the mass of a star is approximately equal to or less than the mass of the Sun, The star would become a red giant, and then turns in a planetary nebula with a white dwarf in the center.
If the mass of a star is much larger than that of the Sun, the star would turns into a red super giant, later it would turns into a stellar nebula, with a neutron star or a black hole in the center
| s23 qp43 Q9(c) iii |
| The average density of Jupiter is much less than that of the Earth. The gravitational field strength at the surface of Jupiter is greater than that at the surface of the Earth. Explain how these differences in density and in gravitational field strength are consistent with your answers to (c)(i). |
| density: Jupiter has a low density because it is composed of gas Earth has a high density because it is rocky/solid gravitational field: Jupiter (has a large GFS so it) has a much larger mass/Earth (has a small GFS so it) has a small mass Jupiter’s mass is larger than the Earth’s mass because the volume of Jupiter is larger even though the density of Jupiter is smaller 此题难度不大，但是看能不能用英语讲出来； 另外，一个planet表面处的重力场强gravitational field strength与该行星的质量和半径有关系；质量越大，场强越大；半径越小，场强也是越大的。英文表述： The larger the mass of the planet is, the greater gravitational field strength would be (keeping the radius of the planet constant); The smaller the radius of the planet is, the greater gravitational field strength would be (keeping the mass of the planet constant); |