Electrical quantities — Paper 4 · IGCSE Sciences - Co-ordinated (Double) 0654

11 (a) A small quantity of radioactive material is taken from a nuclear reactor. Describe how a scientist could prove that the material is releasing γ-rays but not α-particles or β-particles. … … … … … [3] (b) The nuclear fuel used in a power station is plutonium-239. 239 94 Pu decays by α-emission to produce an isotope of uranium. Use the correct nuclide notation to write a symbol equation for this decay process. 239 Pu → … + … 94 [2] (c) The electricity produced in a nuclear power station is transferred from the power station to a nearby town using overhead power cables. The resistance of a length of cable may be calculated using the equation shown. length resistance = constant × cross-sectional area One length of an overhead power cable has a resistance of 7.0 Ω. Predict the resistance of a cable that has half the diameter but is the same length. resistance = … Ω [2] (d) The power station uses generators to generate electricity. Fig. 11.1 shows a simple generator. N S slip rings V Fig. 11.1 A voltage is generated when a coil of wire is turned in a magnetic field. The voltage is measured using a voltmeter connected across slip rings as shown in Fig. 11.1. (i) On the grid in Fig. 11.2, sketch a graph of voltage output against time for the generator, when the coil is rotating at constant speed. voltage output time Fig. 11.2 [2] (ii) State one way in which the size of the induced voltage can be increased. … … [1] (e) A generator is very noisy and emits sound waves which pass through the air. The speed of sound waves in air is 340 m / s. The frequency of the sound waves is 490 Hz. (i) Calculate the wavelength of the sound waves. State the formula you use and show your working. formula working wavelength = … m [2] (ii) Fig. 11.3 represents a sound wave travelling through the air from the generator. direction of travel Fig. 11.3 On Fig. 11.3, label a compression with the letter C. [1] (iii) The generator turns faster and the frequency of the sound emitted increases. Suggest how the distance between two compressions changes. … [1]

14 marks

Mark scheme: 11(a) use Geiger counter etc. ; test for absorption by shield of lead / thick aluminium ; γ-rays are more penetrating than α or β / α and β will not penetrate lead ; OR measure deflection by magnetic / electric field ; γ-rays not deflected / α and β deflected ; 3 11(b) U 235 92 ; He 4 2 OR 4 2 α ; 2 11(c) correct working ; 28 (Ω) ; 2 11(d)(i) approx sin wave ; constant amplitude ; 2 11(d)(ii) stronger magnet / spin coil faster / greater number of turns / increased coil area ; 1 11(e)(i) λ = v / f / 340 / 490 ; = 0.69 (m) ; 2 11(e)(ii) compression correctly labelled ; 1 11(e)(iii) decreases / closer together ; 1

This question in 0654/41 May/June 2017

13 (a) Fig. 13.1 shows information which is on the label attached to a washing machine. voltage 240 V frequency 50 Hz power 2.5 kW Fig. 13.1 (i) Show that the current in the washing machine when in use is 10.4 A. State the formula you use and show your working. formula working [2] (ii) The fuse in the electrical supply to the washing machine has to be replaced. The current through the washing machine when in use is 10.4 A. Three fuses with different current ratings are available and shown in the list below. 10 A 13 A 30 A Explain why only the 13 A fuse should be used. … … … [2] (b) Some washing machines have relays in their circuits. Fig. 13.2 shows a simple relay. contacts high-voltage pivot circuit soft iron soft iron solenoid coil low-voltage circuit Fig. 13.2 Suggest why the contacts close when a current passes through the solenoid coil. … … … [2] (c) Fig. 13.3 represents a sound wave travelling through the air from the washing machine. direction of travel Fig. 13.3 (i) On Fig. 13.3, label a compression with the letter C and a rarefaction with the letter R. [2] (ii) On Fig. 13.3, mark one wavelength with a double headed arrow (↔). [1]

9 marks

Mark scheme: 13(a)(i) (2.5 × 1000) / 240 = 10.4 ; 2 13(a)(ii) must be higher than 10.4 / not 10 A fuse, or else it will blow (with normal current) ; not 30 A fuse if there is a fault too much current will pass through / causes damage to washing machine / causes fire ; 2 13(b) electromagnet / magnetic field created around solenoid coil ; soft iron (armature), attracted to magnet / turns, and closes contacts ; 2 13(c)(i) compression correctly labelled ; rarefaction correctly labelled ; 2 13(c)(ii) one wavelength correctly identified ; 1

This question in 0654/42 May/June 2017

9 (a) A boy riding his bicycle is cooled by sweating. Describe, in terms of molecules, how sweating cools his body by evaporation. … … … … … [3] (b) Fig. 9.1 shows a car behind a bicycle at night. Fig. 9.1 A reflector on the back of the bicycle is made from many small red plastic prisms, one of which is shown in Fig. 9.2. A ray of light from the headlamp of the car enters the prism. ray of light from the headlamp of the following car red plastic prism Fig. 9.2 Total internal reflection occurs within the prism. On Fig. 9.2, complete the path taken by the ray of light until it emerges from the prism. [2] (c) The bicycle has a lamp powered by a small generator. The generator turns as the boy pedals and the lamp lights up. Fig. 9.3 shows a simple version of the generator. axle magnet magnet N S slip ring coil brush lamp Fig. 9.3 Describe how the rotating coil causes the lamp to light. … … … … … … [3] (d) The generator produces an alternating voltage. Fig. 9.4 shows how the output voltage of the bicycle generator changes with time. 6.0 4.0 2.0 voltage / V 0 time / s 0.02 0.04 0.06 0.08 0.10 –2.0 –4.0 –6.0 Fig. 9.4 (i) Calculate the frequency of the alternating voltage. Show your working. frequency = … Hz [1] (ii) State the amplitude of the alternating voltage. amplitude = … V [1] (e) A different bicycle has a front lamp, A, and a rear lamp, B, powered by the same battery. Fig. 9.5 shows how the lamps are connected. 12 V A B Fig. 9.5 (i) State the name given to this arrangement of lamps in a circuit. … [1] (ii) Lamp A has a resistance of 5 Ω. The battery has a voltage of 12 V. Calculate the current flowing through lamp A when the switch is closed. State the formula you use and show your working. formula working current = … A [2] (iii) Lamp B has a resistance of 10 Ω. Calculate the combined resistance of the two lamps in this circuit. Show your working. resistance = … Ω [2]

15 marks

Mark scheme: 9(a) fastest moving / most energetic molecules escape ; remainder are slower / have less energy ; energy used taken from surroundings / molecules gain energy from body ; 3 9(b) first 90° reflection correct ; second 90° reflection correct ; 2 9(c) rotation of coil, cuts magnetic field / experiences changing magnetic field ; induces an emf ; current flows through lamp / pd across lamp causes lamp to light ; 3 9(d)(i) frequency = 25 (Hz) ; 1 Question Answer Marks 9(d)(ii) amplitude = 5 (V) ; 1 9(e)(i) parallel ; 1 9(e)(ii) I = V / R or 12 / 5 ; 2.4 (A) ; 2 9(e)(iii) 1 2 1 2 T R R R R R = + or R = 10 / 3 (Ω) ; = 3.3 (Ω) ; 2

This question in 0654/42 Oct/Nov 2017

10 (a) Fig. 10.1 shows the speed-time graph for the journey of a bus along a road for 80 seconds. 10 9 8 7 6 speed 5 m / s 4 3 2 1 0 0 10 20 30 40 50 60 70 80 time / s Fig. 10.1 (i) Calculate the distance travelled by the bus in 80 seconds. Show your working. distance = … m [3] (ii) The mass of the bus is 8000 kg. Calculate the maximum kinetic energy of the bus during the journey. State the formula you use and show your working. formula working kinetic energy = … J [3] (b) The bus has four wheels. Each wheel has a tyre inflated with air. After a long journey, the tyres are hot and the air pressure in the tyres has increased. (i) Describe how the air molecules in a tyre exert a pressure on the wall of the tyre. … … … [2] (ii) Explain, in terms of molecules, why the pressure of the air in the tyres increases when the temperature increases. … … … [2] (c) The bus has two headlights, L1 and L2. The lamp inside headlight L1 is connected in parallel with the lamp inside headlight L2 across a 12 V battery. Fig. 10.2 shows the circuit diagram for this arrangement. 12 V L1 L2 Fig. 10.2 (i) A current of 3.0 A flows through each lamp for 80 seconds. Calculate the total charge that flows through the two lamps. State the formula you use, show your working and state the unit of your answer. formula working charge = … unit … [3] (ii) The resistance of each lamp is 4.0 Ω. Calculate the combined resistance of the two lamps connected in parallel. Show your working. resistance = … Ω [2] (d) Some of the bodywork on the bus is made from iron. Other parts are made from steel. Both iron and steel are magnetic. Describe one difference between the magnetic properties of iron and the magnetic properties of steel. … … [1]

16 marks

Mark scheme: 10(a)(i) evidence of area under graph ; = 160 + 240 + 75 ; 475 (m) ; 3 10(a)(ii) max speed = 8 m / s ; KE = ½ m v2 OR ½ × 8000 × 8 × 8 ; = 256 000 (J) ; 3 10(b)(i) particles collide with tyre / walls / it ; exert a force (on the tyre wall) ; 2 10(b)(ii) particles are moving faster / more (kinetic) energy ; greater rate of collision / more energetic collisions ; more force exerted (on tyre walls) ; max 2 10(c)(i) Q=It OR 3 × 80 OR 240 ; 2 × 240 OR 480 ; C ; 3 10(c)(ii) correct formula / substitution / explanation ; 2.0 (Ω) ; 2 10(d) iron magnetises quickly / steel magnetises slowly / iron loses magnetism quickly / steel loses magnetism slowly ; 1

This question in 0654/43 Oct/Nov 2017

12 (a) An electric cooker connected to a mains supply of 240 V has a power input of 6000 W. (i) Show that the current that flows is 25 A. State the formula you use and show your working. formula working [2] (ii) The cooker has its own circuit breaker. Explain why a circuit breaker rated at 20 A must not be used in the cooker circuit. … … … … [2] (b) Fig. 12.1 shows some water being heated in a saucepan on the hotplate of the cooker. water saucepan hotplate not to scale Fig. 12.1 The weight of the saucepan and water is 25 N. The area of the saucepan in contact with the cooker hotplate is 300 cm2. (i) Calculate the area of the saucepan in contact with the hotplate in m2. area = … m2 [1] (ii) Calculate the pressure exerted by the saucepan on the surface of the hotplate in Pa. State the formula you use and show your working. formula working pressure = … Pa [2] (c) Fig. 12.2 shows a graph of the temperature of the water as it is heated for 1000 s. 110 100 90 80 70 60 temperature / °C 50 40 30 20 10 0 0 100 200 300 400 500 600 700 800 900 1000 time / s Fig. 12.2 (i) The mass of the heated water is 1.5 kg. The specific heat capacity of water is 4200 J / (kg °C). Calculate the energy required to heat the water to 100 °C. State the formula you use and show your working. formula working energy = … J [3] (ii) Before the water boils, some of the water evaporates. State two ways in which boiling differs from evaporation. 1 … … 2 … … [2]

12 marks

Mark scheme: 12(a)(i) P V = I ; = 6000 240 ; 2 12(a)(ii) breaker would trip at working current ; breaking current should be more than current rating of device OR 20A < 25A / working current ; 2 12(b)(i) 0.03 (m2) ; 1 12(b)(ii) F P A = OR 25 0.03 ; = 830 (Pa) ; 2 12(c)(i) temp rise = 80°C ; E = m c ∆T OR 1.5 × 4200 × 80 ; = 504 000 (J) ; 3 Question Answer Marks 12(c)(ii) evaporation can occur at any temperature / boiling only happens at the boiling point ; evaporation happens only at the surface / boiling happens throughout the liquid ; boiling takes energy in to occur / evaporation lets only the molecules with the highest kinetic energy out ; evaporation can occur using the internal energy of the system / boiling requires an external source of heat ; evaporation produces cooling / boiling does not produce cooling ; evaporation is a slow process / boiling is a rapid process ; max 2

This question in 0654/43 Oct/Nov 2017

9 (a) In the school science laboratory, a student investigates how the resistance of a circuit component Z changes with temperature. Fig. 9.1 shows his results. 20 18 resistance / ohms 16 14 12 10 8 6 4 2 0 0 20 40 60 80 100 temperature / °C Fig. 9.1 (i) Name component Z. … [1] (ii) State the resistance of component Z at 20 °C. … Ω [1] (iii) Calculate the current passing through component Z at 20 °C when a 6 V supply is connected across it. State the formula you use and show your working. formula working current = … A [2] (b) To change the temperature around component Z, it is placed in a plastic bag in a water bath. The water bath contains 4.0 kg of water at an initial temperature of 15 °C. To raise the temperature of the water to 80 °C requires 1087 kJ. Calculate the specific heat capacity of water. State the formula you use and show your working. formula working specific heat capacity = … kJ / (kg°C) [2] (c) At the end of the lesson, a bell rings. The bell produces sound waves. The sound waves travel through the air as a series of compressions and rarefactions. Describe, in terms of particles, the difference between a compression and a rarefaction. … … [1]

7 marks

Mark scheme: 9(a)(i) thermistor ; 1 9(a)(ii) 10 (Ω) ; 1 9(a)(iii) current = voltage / resistance or 6 / 10 ; = 0.6 (A) ; 2 9(b) or 1087 4.0 65 × ; C = = 4.2 (kJ / (kg oC)) ; 2 9(c) compression region of high pressure / where the particles are close together ; 1

This question in 0654/43 Oct/Nov 2018

3 Fig. 3.1 shows a motorcycle with a rear lamp. rear lamp Fig. 3.1 (a) The lamp has a resistance of 30 Ω and is powered by a 12 V battery. (i) Show that the current in the lamp is 0.40 A. [1] (ii) Calculate the power used by the lamp. Show your working. power = … W [2] (iii) Calculate the charge that passes through the lamp in 30 minutes. Show your working. charge = … C [2] (b) The battery is charged by an a.c. generator. Fig. 3.2 shows a simple a.c. generator. N S a.c. output Fig. 3.2 (i) On Fig. 3.2, label the slip rings with the letter R. [1] (ii) On Fig. 3.2, label the coil with the letter C. [1] (iii) On Fig. 3.2, show the direction of the magnetic field with an arrow ( ). [1] (iv) The output is an alternating current. Describe the difference between direct current (d.c.) and alternating current (a.c.). … … … [1] (c) The motorcycle engine is noisy and emits sound waves that pass through the air. The sound waves pass through the air as a series of compressions (C) and rarefactions (R). Fig. 3.3 shows the positions of the compressions and rarefactions as the sound wave passes through the air. C R C R C R C R C R Fig. 3.3 Suggest how and explain why the positions of the compressions and rarefactions change if the pitch of the sound increases. … … … [3]

12 marks

Mark scheme: 3(a)(i) 12/30 = 0.4 (A) ; 1 3(a)(ii) voltage × current or 12 × 0.40 ; = 4.8 (W) ; 2 3(a)(iii) current × time or 0.4 × 30 (× 60) or 0.4 × 1800 ; =720 (C) ; 2 3(b)(i) correct label ; 1 3(b)(ii) correct label ; 1 3(b)(iii) arrow drawn from N to S ; 1 3(b)(iv) direct current goes in one direction / alternating current changes direction ; 1 3(c) higher frequency / more waves produced per second ; shorter wavelength ; compressions and rarefactions get closer together ; 3

This question in 0654/41 May/June 2019

9 Fig. 9.1 shows a potato being baked in the oven of an electric cooker. Fig. 9.1 (a) The potato has a steel skewer (a long metal pin) pushed through it. When heated the metal skewer expands. Explain in terms of the motion and arrangement of molecules why a solid expands less than a gas when heated. … … … … [2] (b) A thermocouple is used to measure the temperature inside the oven. Describe the structure of a thermocouple. … … [1] (c) The cooker has one electrically heated hotplate. The hotplate uses a current of 2.0 A when used with a mains voltage of 230 V. (i) Calculate the resistance of the hotplate. Show your working. resistance = … Ω [2] (ii) Calculate the energy supplied to the hotplate in 1200 seconds. Show your working. energy = … J [2] (iii) Some water is heated in a saucepan and turns to steam. Describe the differences between water and steam in terms of the forces and distances between the molecules and the motion of the molecules. … … … … [3] [Total: 10]

10 marks

Mark scheme: 9(a) particles in a gas are not/weakly bonded ; particles in a gas move further apart ; 2 9(b) two different metals joined together ; 1 9(c)(i) (R =) V / I or 230 / 2.0 ; = 120 / 115 (Ω) ; 2 9(c)(ii) (E =) V × I × t or 230 × 2.0 × 1200 ; 550 000 / 552 000 (J) ; 2 9(c)(iii) stronger forces of attraction between molecules in liquid water ; molecules are closer together in liquid water ; molecules in liquid water move around each other or molecules in steam move throughout the gas / move further between collisions ; 3

This question in 0654/43 May/June 2019

12 (a) Fig. 12.1 shows a gardener using a leaf-blower. Fig. 12.1 Fig. 12.2 shows the energy input and outputs for the leaf-blower. useful total energy energy output input wasted energy output Fig. 12.2 Calculate the efficiency of the leaf-blower as a percentage. Show your working. efficiency = … % [2] (b) When used the leaf-blower takes a current of 3.0 A. Calculate the charge that flows through the leaf-blower when it is used for 180 seconds. Show your working. charge = … C [1] (c) The leaf-blower contains a small electric motor powered by a battery. Fig. 12.3 shows a simple electric motor powered by a battery. coil N S electric current Q Fig. 12.3 (i) State the name of the component labelled Q on Fig. 12.3. name of component Q … [1] (ii) Draw an arrow on Fig. 12.3 to show the direction of the magnetic field. [1] (iii) Explain why the coil moves when an electric current passes through it. … … … … [3] [Total: 8]

8 marks

Mark scheme: 12(a) = 37.5% ; 2 12(b) (charge = current x time = 3 × 180 =) 540 (C) ; 1 12(c)(i) split ring commutator ; 1 12(c)(ii) arrow from N pole to S pole ; 1 12(c)(iii) current produces magnetic field (around coil) ; magnetic field interacts with other magnetic field ; force exerted (on current carrying conductor in magnetic field) ; 3

This question in 0654/43 May/June 2019

6 (a) An iron magnet picks up two iron nails as shown in Fig. 6.1. S N Fig. 6.1 Explain why the nails do not hang vertically. … … … [2] 60 (b) An isotope of iron has a nuclide notation 26Fe and decays by beta particle emission to an isotope of cobalt. (i) State what is meant by the term isotope. … … [1] (ii) Use nuclide notation to complete the symbol equation for this β-decay process. [2] 6026Fe … + … (c) An iron wire of length 0.50 m has a cross sectional area of 4.0 × 10–5 m2 and a resistance of 1.21 × 10–3 Ω. Calculate the resistance of an iron wire of length 0.25 m that has a cross sectional area of 8.0 × 10–5 m2. resistance = … Ω [3] (d) A block of iron is on a bench. The surface of the block of iron in contact with the bench has an area of 144 cm2. The mass of the block of iron is 13.6 kg. Calculate the pressure exerted by the block of iron on the bench in N / cm2. gravitational field strength = 10 N / kg pressure = … N / cm2 [3] [Total: 11]

11 marks

Mark scheme: 6(a) ref. to induced magnetism (in) nails ; two nail heads / north poles / like poles, will repel each other ; 2 6(b)(i) atoms having same atomic number / proton number and different mass number / neutron number ; 1 6(b)(ii) 60Co ; 27 0 e ; –1 2 6(c) evidence that resistance is halved by cross sectional area change ; evidence that resistance is halved by length change ; new resistance = 3.0 × 10–4 Ω ; 3 6(d) 136 N ; pressure = force / area OR 136 / 144 ; 0.94 (N / cm2) ; 3

This question in 0654/41 Oct/Nov 2019

12 A fishing boat floats on the sea. (a) A heavy anchor is dropped from the boat and accelerates as it falls through the water to the sea bed. Name the downward force that makes the anchor accelerate. … [1] (b) The boat has a small generator to generate electricity. Fig. 12.1 shows a simple generator. N S Fig. 12.1 (i) On Fig. 12.1 label a slip ring with the letter R. [1] (ii) Describe how the use of slip rings produces an alternating voltage output from the rotating coil. … … … [2] (iii) On the grid in Fig. 12.2, sketch a graph of voltage output against time for the generator, when the coil is rotating at a constant speed. voltage output time Fig. 12.2 [2] (c) An electric heater on the boat uses the electricity generated at 240 V. The current passing through the heater is 20 A. Calculate the charge passing through the heater in one hour. State the unit of your answer. charge = … unit … [3] (d) A fisherman on the boat is using a pair of binoculars to look at the sea. Binoculars use glass prisms to reflect light. Fig. 12.3 shows part of a pair of binoculars. A ray of light is shown entering and leaving. glass prism light ray entering light ray leaving Fig. 12.3 On Fig. 12.3, complete the ray diagram to show the path of the light ray through the two prisms. [1] [Total: 10]

10 marks

Mark scheme: 12(a) weight ; 1 12(b)(i) slip rings labelled correctly ; 1 12(b)(ii) induced voltage changes every half turn ; same side of coil remains connected to same slip ring ; 2 12(b)(iii) approx. sine curve ; regular frequency and amplitude ; 2 12(c) (charge =) current × time or 20 × 1 × 60 × 60 ; 72 000 ; C ; 3 12(d) ray drawn correctly through first prism and through second prism ; 1

This question in 0654/42 Oct/Nov 2019

3 (a) Fig. 3.1 shows a bar magnet suspended by a spring above a coil that is connected to a voltmeter. spring magnet N coil S voltmeter V Fig. 3.1 When the magnet is pulled downwards into the coil and then released, it oscillates up and down inside the coil. An alternating voltage is observed on the voltmeter. Explain why an alternating voltage is observed. … … … [2] (b) A thin piece of iron wire has a diameter of 0.20 mm. (i) Name the device which could accurately measure very small distances such as 0.20 mm. … [1] (ii) The wire is 0.10 m in length and has a resistance of 0.30 Ω. Determine the resistance of a piece of wire made from the same iron metal that is 0.10 m in length but has a diameter of 0.40 mm. resistance = … Ω [2] (c) The isotope iron-55 has a half-life of 2.7 years. A sample of this isotope contains 8 × 1012 atoms. Some time later 7 × 1012 atoms have decayed. Calculate the time needed for this number of atoms to decay. time = … years [3] (d) Fig. 3.2 shows an iron rod being heated at one end by a Bunsen burner. Fig. 3.2 Thermal energy passes through the rod by conduction. (i) Describe the process of conduction in solid iron, using ideas about the vibration of atoms. … … … … [2] (ii) When heated, the iron rod expands. Explain in terms of the motion and arrangement of the atoms why iron expands when heated. … … … [2] [Total: 12]

12 marks

Mark scheme: 3(a) voltage induced as coil cuts magnetic field / induced as magnetic field in coil changes ; voltage reverses when magnet changes direction ; 2 3(b)(i) micrometer screw gauge ; 1 3(b)(ii) doubling diameter quadruples CSA / evidence of dividing by 4 ; 0.075 (Ω) ; 2 3(c) 1 × 1012 atoms undecayed ; 3 half-lives ; (3 × 2.7) = 8.1 (years) ; 3 3(d)(i) (incident energy / energy gained, makes) atoms vibrate more ; this vibration is passed through metal ; 2 3(d)(ii) atoms have greater (amplitude of) vibration ; about a fixed point so take up more space / (average) distance between particles increases / owtte ; 2

This question in 0654/43 Oct/Nov 2019

9 Fig. 9.1 shows a golf cart used to carry golfers and their golf clubs around a golf course. Fig. 9.1 (a) The cart contains an electric motor powered by a 36 V battery. The power rating of the motor is 3000 W. (i) Calculate the maximum current that passes through the motor. current = … A [2] (ii) Calculate the charge flowing through the motor when it is used at a maximum current for 5 minutes. charge = … C [2] (iii) Fig. 9.2 shows a simple d.c. electric motor. N S Fig. 9.2 On Fig. 9.2, label the split-ring commutator with the letter X and the coil with the letter C. [2] (b) A golfer hits a golf ball. At one moment, the golf ball has 22.5 J of kinetic energy. The mass of the golf ball is 50 g. Calculate the speed of the golf ball at that moment. speed = … m / s [2] [Total: 8]

8 marks

Mark scheme: 9(a)(i) current = power / voltage OR 3000 / 36 ; 83 (A) ; 2 9(a)(ii) charge = current × time OR 83 × 5 × 60 ; 25 000 (C) ; 2 9(a)(iii) split ring commutator correctly labelled (X) ; coil correctly labelled (C) ; 2 9(b) E = ½ mv2 OR v = √ (2 E / m) OR √ (2 × 22.5 / 0.05) ; = 30 (m / s) ; 2

This question in 0654/43 Oct/Nov 2019

12 (a) Fig. 12.1 shows an aircraft being refuelled using a plastic pipe. tanker aircraft plastic pipe Fig. 12.1 As the fuel flows through the pipe, the fuel and pipe become electrically charged. Explain why the fuel becomes negatively charged and the pipe becomes positively charged. … … … [2] (b) Fig. 12.2 is the speed-time graph for the aircraft during take-off. 60.0 50.0 40.0 speed 30.0 m / s 20.0 10.0 0.0 10.0 20.0 30.0 40.0 50.0 time / s Fig. 12.2 (i) Calculate the acceleration at 25 seconds. acceleration = … m / s2 [2] (ii) State how the graph shows that the acceleration of the aircraft is constant between 5.0 s and 45.0 s. … … [1] (c) (i) During the flight the pressure inside the aircraft cabin decreases but the temperature is kept constant. Use ideas about gas molecules to describe the change in pressure in terms of the arrangement and motion of molecules. … … … … [2] (ii) The aircraft flies at a high altitude. Some water on the outside of the aircraft body turns to ice. Describe in terms of molecular motion and arrangement how ice differs from liquid water. … … … [2] [Total: 9]

9 marks

Mark scheme: 12(a) transfer of electrons; from pipe to fuel; 2 12(b)(i) correct working (e.g. 50/40) ; 1.25 (m/s2) ; 2 12(b)(ii) straight line; 1 Question Answer Marks 12(c)(i) molecules further apart ; fewer molecules collide with, surfaces / walls, in unit time / lower frequency of collision of molecules with, surfaces / walls ; 2 12(c)(ii) molecular motion – molecules in liquid water can move throughout but molecules in ice vibrate about a fixed point ; molecular arrangement – molecules in liquid water in random arrangement / molecules in ice in regular arrangement ; 2

This question in 0654/41 May/June 2020

9 A mountaineer climbs a mountain. (a) At the top of the mountain there is some ice that is melting in the sunshine. (i) State the melting point of water. … °C [1] (ii) Describe, in terms of molecular motion and arrangement, how liquid water is different from ice. motion … … arrangement … … [2] (b) On the mountain, the mountaineer is exposed to ultraviolet radiation. Ultraviolet radiation is an electromagnetic wave. On Fig. 9.1 write ultraviolet in the correct place in the incomplete electromagnetic spectrum. X-rays visible light radio waves [1] Fig. 9.1 (c) The mountaineer observes lightning striking a nearby mountain. (i) There is an electric field between the negative charge on a cloud and the positive charge on the mountain. State what is meant by an electric field. … … [1] (ii) The lightning occurs when the cloud loses some of its charge to the mountain. The lightning flash discharges 3.0 C in 0.00012 s. Calculate the current that passes. current = … A [2] [Total: 7]

7 marks

Mark scheme: 9(a)(i) 0(°C); 1 9(a)(ii) molecular motion – molecules in liquid water can move throughout but molecules in ice vibrate about a fixed point ; molecular arrangement – molecules in liquid water in random arrangement / molecules in ice in regular arrangement ; 2 9(b) ultraviolet placed between X-rays and visible light; 1 9(c)(i) a region in which an electric charge experiences a force; 1 9(c)(ii) I = Q/t or correct substitution; 25 000 (A); 2

This question in 0654/42 May/June 2020

3 (a) A car travels along a road at 8 m / s. Describe the difference between the terms speed and velocity. … … … [1] (b) Some puddles of water have formed on the road. Explain, in terms of water molecules, how the rate of evaporation of water from a puddle is affected by the strength of the wind blowing across the puddle. … … … … [2] (c) The car battery has an electromotive force (e.m.f.) of 12 V. State what is meant by electromotive force. … … … [2] (d) Fig. 3.1 shows part of the lighting circuit for the car. Two lamps, L1 and L2, each have a resistance of 16 Ω. 12 V fuse L1 L2 Fig. 3.1 (i) When the switch is closed the current in the fuse is 1.5 A. Determine the current in L1. current = … A [1] (ii) State one reason why the lamps are connected as shown in Fig. 3.1 and not in series. Explain your answer. … … … [2] (e) Modern cars use optical fibres to transfer information using visible light rays. Fig. 3.2 shows a ray of light entering an optical fibre. ray of light optical fibre Fig. 3.2 (i) Explain why the ray of light is able to stay inside the optical fibre. You may draw on Fig. 3.2 if it helps your answer. … … … … [2] (ii) Visible light rays are transverse waves. Draw labelled diagrams to show the difference between a transverse wave and a longitudinal wave. [2] [Total: 12]

12 marks

Mark scheme: 3(a) speed has magnitude only / velocity has magnitude and direction / velocity has direction / speed does not have direction ; 1 3(b) increase in wind strength increases rate of evaporation / ORA ; (stronger wind) allows more molecules to escape / evaporate into the air above the puddle / ORA ; 2 3(c) the energy / work done (supplied by a source) ; per (unit) charge ; 2 3(d)(i) 0.75 (A) ; 1 Question Answer Marks 3(d)(ii) if one lamp fails the other will still work ; if one lamp fails still a complete circuit ; OR ref. to full brightness / brighter lamps ; because they each receive the full voltage ; 2 3(e)(i) ref. to total internal reflection / owtte / shown on diagram ; angle of incidence greater than the critical angle ; 2 3(e)(ii) correct diagrams for transverse and longitudinal waves ; vibrations perpendicular to direction of travel for transverse and parallel for longitudinal ; 2

This question in 0654/41 Oct/Nov 2020

12 (a) Fig. 12.1 shows a laptop computer and charger. charger laptop Fig. 12.1 The charger contains a transformer. The input voltage across the primary coil is 250 V. The primary coil has 5000 turns. The output voltage from the secondary coil is 19 V. (i) Explain why this transformer is called a step‑down transformer. … … [1] (ii) Calculate the number of turns on the secondary coil. number of turns = … [2] (b) The laptop computer has a rechargeable battery. The battery takes 2 hours to charge fully when a voltage of 19 V is used with a current of 1.1 A. Calculate the energy transferred during the 2 hours. energy = … J [3] (c) Fig. 12.2 shows the laptop computer being closed by a force of 12 N. 12 N 24 cm pivot Fig. 12.2 Calculate the moment of the force about the pivot. moment = … N m [2] (d) The microprocessor in the laptop generates large quantities of thermal energy. The thermal energy must be removed so that the microprocessor does not overheat. Fig. 12.3 shows a heat sink placed in contact with the microprocessor. black metal fins heat sink microprocessor Fig. 12.3 Thermal energy is conducted from the microprocessor into the metal fins of the heat sink. Suggest and explain two ways in which the design of the heat sink allows thermal energy to be removed efficiently from the heat sink. 1 … … 2 … … [2] [Total: 10]

10 marks

Mark scheme: 12(a)(i) voltage is lowered ; 1 12(a)(ii) (NS =) NPVS/VP or 5000 × 19/250 ; number of coils = 380 ; 2 12(b) 2 hours = 2 × 3600 = 7200 s; (energy =) VIt / 19 × 1.1 × 7200 ; (energy =) 150 000 (J) ; 3 12(c) (moment =) force × (perpendicular) distance or 12 × 24(/100) ; 2.9 (Nm) ; 2 Question Answer Marks 12(d) black surfaces are good emitters of thermal energy ; large surface area enables efficient convection; 2

This question in 0654/41 Oct/Nov 2020

12 (a) Fig. 12.1 shows a truck crossing a bridge. Fig. 12.1 The bridge is designed with gaps in the road surface as shown in Fig. 12.2. road surface metal strip gaps Fig. 12.2 The temperature of the road surface increases on a hot day. (i) Describe what happens to the gaps in the road surface when the temperature increases. Explain your answer. … … … [2] (ii) Suggest what may happen to the bridge if there were no gaps in the road surface. … … [1] (b) Fig. 12.3 shows the fuel tank of the truck being filled with diesel fuel. – – – – – – – + + – + + + + + + + + + + ++ + delivery diesel pipe fuel fuel tank Fig. 12.3 Explain why the diesel fuel becomes positively charged. … … … [2] (c) The truck has a warning triangle to alert other drivers. Fig. 12.4 shows the warning triangle. Fig. 12.4 Many tiny prisms are contained in the warning triangle. Fig. 12.5 shows one ray of light entering a prism. Fig. 12.5 The ray undergoes total internal reflection inside the prism. Complete Fig. 12.5 to show the path of the ray of light through the prism and the ray of light leaving the prism. [2] (d) The truck has a generator. Fig. 12.6 shows a simple generator producing an alternating voltage. Fig. 12.6 (i) On Fig. 12.6, label the coil C. [1] (ii) On Fig. 12.6, label the slip rings S. [1] (iii) Describe how turning the coil induces an alternating voltage. … … … … [3] [Total: 12]

12 marks

Mark scheme: 12(a)(i) gap closes ; road expands in the heat ; 2 12(a)(ii) (the road will) buckle / bend / break / be damaged ; 1 Question Answer Marks 12(b) ref to friction / described ; transfer of electrons ; from the fuel (to the pipe) ; max 2 2 12(c) reflection only shown at first reflection ; after second reflection ray emerges parallel to incident ray ; 2 12(d)(i) coil correctly labelled ; 1 12(d)(ii) slip rings correctly labelled ; 1 12(d)(iii) magnetic field ; rotating coil cuts magnetic field or flux / experiences a changing magnetic field ; e.m.f. / current reverses every half turn ; 3

This question in 0654/42 Oct/Nov 2020

9 Visible light is a transverse wave and is part of the electromagnetic spectrum. (a) State what is meant by a transverse wave. … … [1] (b) Fig. 9.1 shows a ray of visible light from a torch (flashlight) shining into a rectangular glass block. glass air Fig. 9.1 (i) Complete Fig. 9.1 to show the path the ray takes through and out of the block. [2] (ii) State the term used to describe what happens to the ray of light as it enters the glass block. … [1] (iii) Explain why this happens to the ray of light. … … [1] (c) Fig. 9.2 shows the electrical circuit used in the torch. Fig. 9.2 When the switch is closed, the current in the lamp is 1.8 A and the potential difference across the lamp is 3.0 V. Calculate the power output of the lamp. power = … W [2] (d) Fig. 9.3 shows two lamps, identical to the torch lamp, connected in parallel. A Fig. 9.3 (i) When the switch is closed, the ammeter reads 2.6 A. State the current in each lamp. current = … A [1] (ii) Calculate the quantity of charge passing through one of the lamps in Fig. 9.3 when it is switched on for 30 seconds. Give the correct unit for your answer. charge = … unit = … [3] [Total: 11]

11 marks

Mark scheme: 9(a) vibrations / oscillations, are perpendicular to direction of energy transfer ; 1 9(b)(i) ray moves towards the normal inside glass block ; ray emerges parallel to incidence ray ; 2 9(b)(ii) refraction ; 1 9(b)(iii) change of speed / caused by change in density of medium ; 1 9(c) (P=) IV / 1.8 × 3.0 ; 5.4 (W) ; 2 9(d)(i) 1.3 (A) ; 1 Question Answer Marks 9(d)(ii) (Q =) It / 1.3 × 30 ; 39 ; C / Coulombs ; 3

This question in 0654/42 Feb/March 2021

3 Fig. 3.1 shows a kettle and the label on the bottom of the kettle. The kettle contains a heating element inside its base. The kettle is made of white plastic. label power = 2400 W voltage = 240 V heating element Fig. 3.1 (a) Explain, in terms of thermal energy transfer, why the kettle is: (i) made of plastic. … … [1] (ii) white. … … [1] (b) (i) The kettle is filled with cold water and switched on. Describe, in terms of density changes, how the heating element heats up all of the water. … … … … … … [3] (ii) Calculate the current in the heating element. State the unit for your answer. current = … unit = … [3] (iii) Show that the resistance of the heating element is 24 Ω. [1] (iv) The heating element is connected in parallel with a 12 Ω resistor. Calculate the combined resistance of the heating element and the resistor. resistance = … Ω [2] [Total: 11]

11 marks

Mark scheme: 3(a)(i) (plastic is a) poor conductor / good insulator (of thermal energy) ; 1 3(a)(ii) (white objects) emit less (thermal) radiation ; 1 3(b)(i) convection (currents); water at the bottom is heated and density decreases ; hot water then rises and displaces (cold) water towards heater ; 3 Question Answer Marks 3(b)(ii) (I =) P / V or 2400 / 240 ; 10 ; A / amps / amperes ; 3 3(b)(iii) 240 / 10 ; 1 3(b)(iv) 1 / R = 1 / R1 + 1 / R2 / 1 / 24 + 1 / 12 ; or 1 2 1 2 R R R R + or 24 12 24 12 × + ; 8 (Ω) ; 2

This question in 0654/43 May/June 2021

3 (a) Fig. 3.1 shows four electrical component names and their symbols. Draw lines to match each component name with its symbol. One line has been drawn as an example. component symbol fixed resistor light dependent resistor thermistor variable resistor Fig. 3.1 [2] (b) A student investigates how the resistance of a thermistor changes with temperature. Fig. 3.2 shows the results of this investigation. 25 20 15 resistance (kΩ) 10 5 0 0 10 20 30 40 50 temperature (°C) Fig. 3.2 (i) Using Fig. 3.2, state the temperature when the resistance of the thermistor is 5 kΩ. temperature = … °C [1] (ii) Calculate the total resistance of two identical thermistors placed in series when the resistance of each thermistor is 5 kΩ. total resistance = … kΩ [1] (iii) Calculate the total resistance of two identical thermistors placed in parallel when the resistance of each thermistor is 5 kΩ. total resistance = … kΩ [2] (c) A fixed resistor has a current of 3.4 A passing through it. Calculate the charge passing through the fixed resistor during 25 seconds. State the unit of your answer. charge = … unit … [3] [Total: 9]

9 marks

Mark scheme: 3(a) ;; 2 3(b)(i) 32 (oC) ; 1 3(b)(ii) (total resistance =) 10 (kΩ) ; 1 3(b)(iii) 1 / R = 1 / R + 1 / R or 1 / R = 1 / 5 +1 / 5 ; 2.5 (kΩ) ; 2 3(c) (Q =) I t or 3.4 × 25 ; 85 ; C ; 3

This question in 0654/42 Oct/Nov 2021

9 A student investigates the spring constant of three springs, A, B, and C, using Hooke’s law and the equipment shown in Fig. 9.1. The student: • measures the unloaded lengths of each spring • hangs identical masses from each spring and measures the extended lengths. spring spring spring A B C Fig. 9.1 (a) Table 9.1 shows the results. Table 9.1 unloaded length / cm extended length / cm spring A 2.2 3.4 spring B 4.0 4.3 spring C 1.8 2.6 (i) Spring A has a spring constant of 0.50 N / cm. Calculate the weight of the mass hanging from spring A. weight = … N [3] (ii) In the investigation, the student hangs identical masses from each spring. State and explain which of the three springs has the largest spring constant. spring … explanation … … … [2] (b) The springs are all made of metals and conduct electricity. The student sets up a circuit to determine the electrical resistance of one of the springs. Fig. 9.2 shows the circuit used. The ammeter reads 0.75 A and the voltmeter reads 7.5 V. 9 V A 10 Ω spring V Fig. 9.2 (i) Calculate the resistance of the metal spring. resistance = … Ω [3] (ii) The spring acts like a solenoid when there is a current in it. Draw on Fig. 9.3 to show the shape, and direction, of the magnetic field due to the current in the solenoid. direction of current Fig. 9.3 [2] [Total: 10]

10 marks

Mark scheme: 9(a)(i) extension = 3.4 – 2.2 = 1.2 (cm) ; (F = ) kx or 0.50 × 1.2 ; (F = ) 0.6 N ; 9(a)(ii) B and smallest extension ; extension is inversely proportional to spring constant ; 2 Question Answer Marks 9(b)(i) pd across spring = 9 – 7.5 = 1.5 (V) ; (R =) V / I or 1.5 / 0.75 ; (R =) 2 (Ω) ; OR combined resistance = V / I or 9 / 0.75 or 12 Ω; resistance of spring = combined resistance – 10 Ω; resistance of spring = 2 (Ω) ; 3 9(b)(ii) correct shape ; correct direction ; 2

This question in 0654/42 Feb/March 2022

9 A student investigates the effect of changing light levels on the resistance of a light-dependent resistor (LDR). The student shines a torch (flashlight) on to the LDR. She then places glass slides between the LDR and the torch (flashlight) to reduce the light intensity (amount of light) reaching the LDR. Fig. 9.1 shows the equipment she uses. torch (flashlight) resistance meter glass slide 340 V A LDR kΩ Fig. 9.1 The student places more glass slides between the torch (flashlight) and the LDR and measures the resistance, in kilo-ohms (kΩ), using a resistance meter. (a) Fig. 9.2 shows a graph of the student’s results. 900 800 700 600 500 resistance / kΩ 400 300 200 100 0 0 1 2 3 4 5 6 number of glass slides Fig. 9.2 (i) Use Fig. 9.2 to describe how the resistance of the LDR varies with changing light intensity. … … … … [2] (ii) The resistance meter provides a potential difference (p.d.) of 14 V across the LDR. Calculate the charge flowing through the LDR in 1 minute when 3 glass slides are used. charge = … C [4] (b) The lamp emits visible light at a frequency of 5.0 × 1014 Hz. (i) State the meaning of the word frequency. … … [1] (ii) Calculate the wavelength of this visible light. wavelength = … m [3] (iii) State one form of electromagnetic radiation that has a frequency higher than visible light. … [1] [Total: 11]

11 marks

Mark scheme: 9(a)(i) resistance increases as light intensity decreases ; increase is smallest for lower light intensity ; 2 9(a)(ii) (R =) 700 (k) ; (I =) V / R OR 14 / 700000 / 0.00002 (A) ; (Q =) It OR 0.00002  60 ; 0.0012 (C) ; 4 9(b)(i) The number of oscillations per second / number of waves passing a point per second ; 1 9(b)(ii) (v =) 3  108 (m / s) ; ( =) v / f OR   8 14 3 10 5.0 10 ; 6.0  10–7 (m) ; 3 9(b)(iii) any one of: gamma / X-rays / UV ; 1

This question in 0654/43 May/June 2022

9 A student investigates the effect of changing temperature on the current through a thermistor. The student connects a cell, an NTC thermistor, an ammeter and a switch in series. (a) On Fig. 9.1, complete the circuit diagram to show the circuit used by the student. Fig. 9.1 [2] (b) The graph in Fig. 9.2 shows the results obtained by the student. 30 25 20 current / mA 15 10 5 0 0 20 40 60 80 100 temperature / °C Fig. 9.2 The temperature of the thermistor is 40 °C. Calculate the time it takes for 1.0 C of charge to flow through the thermistor. time = … s [3] (c) The student uses a liquid-in-glass thermometer to measure temperature. Fig. 9.3 shows the structure of a liquid-in-glass thermometer. glass ethanol Fig. 9.3 (i) Thermal energy is transferred through the glass to the ethanol. Describe how thermal energy is transferred through glass. … … … [2] (ii) The ethanol in the thermometer expands as the temperature increases. Explain why the ethanol expands as the temperature increases in terms of the motion and arrangement of molecules. … … … … [2] (iii) The volume of the ethanol in the thermometer at 25 °C is 2.00 cm3 and the density of the ethanol is 0.78 g / cm3. When the thermometer is cooled to 3 °C, the volume decreases to 1.95 cm3. Calculate the density of the ethanol at 3 °C. density of ethanol = … g / cm3 [3] [Total: 12]

12 marks

Mark scheme: 9(a) 2 correct symbols ; correct circuit ; 9(b) (from graph I =) 5 (mA) / 0.005 (A) ; 3 (t =) Q / I or 1 / 0.005 ; (t =) 200 (s) ; 9(c)(i) conduction ; 2 vibrations passed from particle to particle ; 9(c)(ii) kinetic energy / speed of molecules increases ; 2 molecules move further apart ; 9(c)(iii) (m =) ρ  V OR 0.78  2.0 OR 1.56 (g) ; 3 (ρ =) m / V OR 1.56 / 1.95 ; (ρ =) 0.80 (g / cm3) ;

This question in 0654/41 Oct/Nov 2022

6 Fig. 6.1 shows a temporary zebra enclosure in a wildlife conservation park. The enclosure is surrounded by an electric fence. Fig. 6.1 (a) The fence is powered by an e.m.f. of 2000 V and carries a current of 80 mA. (i) Calculate the total resistance of the fence. total resistance = … Ω [3] (ii) The fence is made of two identical cables connected in parallel. The cables act as resistors. Fig. 6.2 shows the circuit used in the electric fence. cables Fig. 6.2 Use your answer to 6(a)(i) to calculate the resistance of one of the cables. resistance = … Ω [2] (iii) A different enclosure uses a fence made of cables that are the same thickness but twice the length of those shown in Fig. 6.1. State the effect of doubling the cable length on the resistance of the fence. … [1] (b) One of the zebras is startled by a loud sound. (i) Describe how sound waves are transmitted in air. … … [1] (ii) After hearing the sound, the zebra runs across the enclosure in 7.5 s. The average speed of the zebra is 16 m / s. Calculate the distance the zebra runs. distance = … m [2] (c) Fig. 6.3 shows one of the zebras in the enclosure. The zebra has black and white stripes. Fig. 6.3 A vet uses an infrared camera to measure the temperature of the zebra. The infrared camera shows that the black stripes are a different temperature to the white parts of the zebra. Describe and explain the difference in temperature recorded. … … … … [2] [Total: 11]

11 marks

Mark scheme: 6(a)(i) (I =) 0.08 A ; 3 (R =) V / I or 2000 / 0.08 ; (R =) 25000 (Ω) ; 6(a)(ii) use of 1 / RT =1 / R + 1 / R ; 2 (R =) 50000 (Ω) ; 6(a)(iii) (resistance) doubles ; 1 6(b)(i) rarefaction and compressions ; 1 6(b)(ii) (d =) v  t or 167.5 ; 2 (d =) 120 (m) ; 6(c) black will show the higher temperature / ORA ; 2 black emits more (infrared) radiation than white ;

This question in 0654/42 Oct/Nov 2022

2 Fig. 2.1 shows a person removing a damaged branch from a tree. Fig. 2.1 (a) The damaged branch has a mass of 225 kg and is lowered 5.2 m to the ground. Calculate the change in gravitational potential energy (GPE) of the branch as it is lowered to the ground. The gravitational field strength, g = 10 N / kg. change in GPE = … J [2] (b) The damage to the tree was caused by a lightning strike during a thunderstorm. (i) A scientist estimates that the lightning strike transferred 6000 C of charge in 0.20 s. Calculate the average current in the lightning strike. current = … A [2] (ii) The thunderstorm produces both light and sound waves. Explain why an observer sees the light before they hear the sound. … … … … [2] (c) Lightning is caused by electrostatic charges in clouds. Fig. 2.2 shows how charge can form an electric field inside the cloud. positive charge + + + + + + + + electric field _ _ _ _ _ _ _ _ negative charge Fig. 2.2 (i) Fig. 2.2 shows negative charge at the base of the cloud. State the name of the particles that provide this negative charge. … [1] (ii) Describe what is meant by an electric field. … … [1] (d) Thunderstorms can produce gamma radiation and X‑rays as well as visible light. Use the phrases to complete the sentences. You may use each phrase once, more than once or not at all. less than more than the same as The speed of visible light is … the speed of X‑rays. The wavelength of gamma radiation is … the wavelength of visible light. The frequency of X‑rays is … the frequency of gamma radiation. [2] (e) When lightning passes through the air, it heats the air up to 10 000 °C. State and explain what happens to the volume of the air when the temperature increases. Use ideas about molecules in your answer. … … … … [2] [Total: 12]

12 marks

Mark scheme: 2(a) evidence of (GPE =) mgh (in any form) or 225  10  5.2 ; 2 (GPE =) 11 700 (J) ; 2(b)(i) evidence of (I =) Q / t (in any form) or 6000 / 0.20 ; 2 (I =) 30 000 (A) ; 2(b)(ii) light travels faster than sound ; 2 both waves travel the same distance / over a large distance the difference in time is noticeable ; 2(c)(i) electrons ; 1 2(c)(ii) a region in which charged particles experience a force ; 1 2(d) the same as ; 2 less than AND less than ; 2(e) (volume) increases / expands ; 2 molecules, have more (kinetic) energy / move faster or molecules move further apart ;

This question in 0654/42 Feb/March 2023

9 A student investigates how the resistance of a wire changes with length. Fig. 9.1 shows the equipment she uses. cell ammeter 0.66 1.5 V wire ruler crocodile clips Fig. 9.1 (a) The student moves the crocodile clips to change the length of the wire. She measures this length with the ruler and uses the ammeter reading to calculate the resistance of the wire. When the wire is made longer, the reading on the ammeter decreases. Explain why the reading on the ammeter decreases. … … … … [2] (b) Fig. 9.2 shows a length of wire connected in series with another component labelled X. 1.5 V A wire X V Fig. 9.2 (i) State the name of the component labelled X in Fig. 9.2. … [1] (ii) The student uses the component labelled X to vary the potential difference across the length of wire. The student records the potential difference across the wire and the current in the wire. Fig. 9.3 shows her results. 1.75 1.50 1.25 1.00 potential difference / V 0.75 0.50 0.25 0 0 0.20 0.40 0.60 0.80 current / A Fig. 9.3 Use Fig. 9.3 to determine the resistance of the wire. resistance = … Ω [2] (c) The student chooses to use a maximum electromotive force (e.m.f.) of 1.5 V. State the meaning of the term electromotive force (e.m.f.). … … [2] (d) On Fig. 9.4, draw the shape and direction of the magnetic field around the current‑carrying wire. direction of current Fig. 9.4 [2] [Total: 9]

9 marks

Mark scheme: 9(a) (as length increases) resistance increases ; (as resistance increase) current decreases / resistance inversely proportional to resistance ; 2 9(b)(i) variable resistor ; 1 9(b)(ii) (resistance = ) V / I / 1.50/ 0.80 ; (resistance = ) 1.9 () ; 2 9(c) energy supplied / (electrical) work done (by a source) ; driving charge around a (complete) circuit / per (unit) charge around a (complete) circuit ; 2 9(d) concentric circle(s) around wire ; direction shown anti-clockwise ; 2

This question in 0654/41 May/June 2023

9 A student is investigating electromagnetic induction by dropping a magnet through a coil of wire. The coil of wire is connected to a device which measures the electromotive force (e.m.f.) induced in the coil. Fig. 9.1 shows the equipment used by the student. N direction of motion of magnet S to device to measure e.m.f. coil of wire Fig. 9.1 (a) Fig. 9.2 shows the induced electromotive force (e.m.f.) measured as the magnet falls through the coil of wire. Fig. 9.2 shows two peaks, X and Y. +0.6 peak X +0.4 +0.2 induced e.m.f . / V 0.0 time / s 0.02 0.04 0.06 0.08 –0.2 –0.4 –0.6 peak Y Fig. 9.2 (i) Explain why: peak X is positive and peak Y is negative … … peak Y has a larger magnitude than peak X. … … [2] (ii) The data in Fig. 9.2 was obtained using a coil made of 800 turns of wire. On Fig. 9.2, sketch the data which would be obtained if a coil containing 400 turns was used with the same magnet. [2] (b) When writing up the results, the student is not sure whether to write about the induced potential difference or the induced electromotive force (e.m.f.). Place ticks in Table 9.1 against each statement that is correct for potential difference and for electromotive force (e.m.f.). You may place one or two ticks in each row. The first row has been done for you. Table 9.1 electromotive potential force (e.m.f.) difference is measured in volts 3 3 is equal to work done per unit charge relates to the energy supplied by the source relates to the energy transferred by a circuit component [2] (c) The coil of wire used in the investigation is made of copper. Copper is a solid. Complete the sentences to describe the arrangement of atoms in a solid and the properties of a solid. In a solid, the arrangement of atoms is … . The forces between atoms are … which allows the atoms to … but keeps them in a … position. [2] (d) Copper is a good thermal conductor. Describe how thermal energy is transferred in copper. … … … … [3] [Total: 11]

11 marks

Mark scheme: 9(a)(i) (peak X is positive and peak Y is negative) 2 S causes peak (X) and N causes peak (Y) (as it passes through coil) ; (peak Y has a larger magnitude than X) (idea that) the magnet is increasing in velocity / speed ; 9(a)(ii) 2 same shape graph drawn with line crossing x-axis at same point ; both peaks lower than original ; 9(b) 2 electromotive potential force (e.m.f.) difference is measured in volts ✓ ✓ is equal to work done per unit charge ✓ ✓ relates to the energy supplied by the source ✓ relates to the energy transferred by a circuit component ✓ ;; 9(c) regular / ordered / a lattice 2 strong vibrate fixed ;; four correct = 2 marks two or three correct = 1 mark 9(d) atoms vibrate ; 3 (idea that) vibrations passed on to next atom ; (idea of) transfer by (free) electrons ;

This question in 0654/41 Oct/Nov 2023

12 A student investigates light dependent resistors (LDRs). Fig. 12.1 shows the circuit the student uses. variable power supply A LDR Fig. 12.1 (a) The ammeter in Fig. 12.1 reads 0.24 A. (i) Calculate the amount of charge flowing through the LDR each minute. State the unit for your answer. charge = … unit … [3] (ii) The student shines a bright desk lamp on the LDR. State and explain the effect this has on the ammeter reading. effect … explanation … … … [2] (iii) The desk lamp emits light with wavelengths ranging from 3.8 × 10–7m to 7.5 × 10–7m. Calculate the minimum frequency of light emitted by the desk lamp. minimum frequency = … Hz [3] (b) The student calculates the resistance of the LDR using the current reading from the ammeter. State what other measurement is required for this calculation. … [1] (c) The variable power supply used by the student uses a transformer to reduce the output. The current in the primary coil of the transformer is 10.5 A and the current in the secondary coil is 4.2 A. The primary coil contains 360 turns and the transformer can be assumed to be 100% efficient. Calculate the number of turns in the secondary coil. number of turns = … [4] [Total: 13]

13 marks

Mark scheme: 12(a)(i) (Q =) It / 0.24  60 ; (in any form) 3 (Q =) 14(.4) ; coulombs / C ; 12(a)(ii) (effect) reading increases ; 2 (explanation) the resistance (of the LDR) decreases ; 12(a)(iii) (f =) speed / wavelength or 3  108 / 7.5  10–7 ; (in any form) 3 use of 3  108 (m / s) ; (f =) 4.0  1014 (Hz) ; 12(b) potential difference / p.d. (across the LDR) ; 1 12(c) use of IpVp = IsVs ; 4 Vp = 4.2 / 10.5 Vs / 0.4 Vs ; (Ns = ) NpVs / Vp / 360/0.4 / 360  2.5 ; (in any form) (Ns = ) 900 ; or use of IpNp = IsNs ; Ns = IpNp / Is ; (10.5  360) / 4.2 ; = 900 ;

This question in 0654/43 Oct/Nov 2023

9 Fig. 9.1 shows two identical infrared heating lamps that are heating two metal cubes. The lamps are at the same distance from the cubes. The lamps are heating each cube for the same time. One lamp is heating the dull white metal cube and the other the dull black metal cube. infrared lamp dull white dull black metal cube metal cube Fig. 9.1 (a) (i) Explain why the temperature of the dull black cube rises more than the temperature of the dull white cube. … [1] (ii) The dull black metal cube is replaced by a shiny black metal cube. Explain why the temperature of the shiny black cube rises less than the temperature of the dull black cube. … [1] (iii) Infrared radiation emitted by the lamps includes radiation with a wavelength of 0.75 mm. Calculate the frequency of this infrared radiation. frequency = … Hz [3] (iv) Thermal energy is conducted through the metal cubes. Describe the process of conduction in a metal. … … … … … … [3] (b) One of the cubes is now filled with hot water. A student uses a digital thermometer containing a thermocouple to measure the temperature of the water inside the cube. (i) Describe the structure of a thermocouple used to measure temperature. … … … [1] (ii) The thermocouple produces an electromotive force (e.m.f.). Place ticks (✓) in Table 9.1 to compare e.m.f. to potential difference. Table 9.1 electromotive electromotive force potential difference force and potential only only difference measured in volts measured using a voltmeter equal to the energy supplied by a source in driving a charge around a circuit [3] [Total: 12]

12 marks

Mark scheme: 9(a)(i) dull black (cube) absorbs (thermal / infrared) radiation better than dull white (cube) ; 1 9(a)(ii) shiny black (cube) reflects radiation (rather than absorbs as the dull surface of black cube does) ; 1 9(a)(iii) use of 3.0  108 (m / s) ; 3 (f =) v /  / 3.0  108 / 0.75  10–3 ; (f =) 4.0  1011 (Hz) ; 9(a)(iv) vibrations (of ions / atoms) ; 3 passes from one ion / atom to the next ; also by electrons moving through metal ; 9(b)(i) two different metal wires joined at two junctions at different temperatures ; 1 9(b)(ii) electromotive force and potential difference ticked ; 3 electromotive force and potential difference ticked ; electromotive force only ticked ;

This question in 0654/42 Feb/March 2024

9 A student investigates the use of cotton wool to insulate a beaker of hot water at 90 °C. (a) The student uses a digital thermometer to measure the temperature of the water in the beaker as it cools. The student repeats the experiment using different thicknesses of cotton wool. Fig. 9.1 shows a graph of the results. 100 80 60 temperature / °C 3.0 cm of insulation 40 1.0 cm of insulation no insulation 20 00 1.0 2.0 3.0 4.0 5.0 time / minutes Fig. 9.1 (i) Predict the temperature after 5.0 minutes of a beaker of water which is insulated with 2.0 cm of insulation. Use the results shown in Fig. 9.1 to explain your answer. temperature … °C explanation … … … [2] (ii) Complete the sentences about the digital thermometer. The digital thermometer contains two wires made of different metals. The wires are joined together at each end to form two junctions. This arrangement is known as a … . [1] (b) The student uses an electric kettle to heat the water for the investigation. The electric kettle has a power rating of 1800 W when a potential difference of 240 V is applied. Calculate the resistance of the kettle. resistance = … Ω [4] (c) Plastic is an electrical insulator. Fig. 9.2 shows two lightweight, plastic sheets suspended by insulating threads. insulating thread plastic sheet Fig. 9.2 Each plastic sheet is positively charged. (i) Explain what is observed when the two plastic sheets are moved close to each other. … … … [2] (ii) Describe how a plastic sheet can become positively charged. … … … … [3] [Total: 12]

12 marks

Mark scheme: 9(a)(i) any temperature in the inclusive range 36–50 (°C) ; 2 2.0 cm reduces the rate of conduction (to the surroundings) more than 1.0 cm but less than 3.0 cm / OWTTE ; 9(a)(ii) thermocouple ; 1 9(b) evidence of (I =) P ÷ V or 1800 ÷ 240 ; 4 (I =) 7.5 (A) ; evidence of R = V ÷ I or 240 ÷ 7.5 ; (R =) 32 () ; 9(c)(i) move away from each other ; 2 like charges repel ; 9(c)(ii) friction (with another surface) ; 3 transfer of electrons ; (particles move) from the plastic / to the surface it is rubbing against ;

This question in 0654/42 Oct/Nov 2024

3 A student investigates an NTC thermistor. (a) The student connects the thermistor in series with a cell and an ammeter. The student also connects a voltmeter to measure the potential difference across the thermistor. Fig. 3.1 shows an incomplete circuit diagram of the circuit used by the student. Fig. 3.1 (i) Complete Fig. 3.1. [2] (ii) When the thermistor is at room temperature, the ammeter reads 3.0 A. Calculate the charge that flows through the thermistor in 60 s. State the unit for your answer. charge = … unit … [3] (b) The student places the thermistor into hot water. The student records the values shown by the ammeter and the voltmeter as the temperature of the thermistor increases. Describe how the power output of the thermistor changes as the temperature of the thermistor increases. … … … … … [4] (c) Fig. 3.2 shows the current–voltage characteristic for an ohmic resistor. current 0 0 voltage Fig. 3.2 Explain the shape of the graph shown in Fig. 3.2. … … … … [2] [Total: 11]

11 marks

Mark scheme: 3(a)(i) correct thermistor symbol in correct place ; 2 A and V correct ; 3(a)(ii) (Q =) It or 3  60 ; 3 (Q =) 180 ; C / coulombs ; 3(b) resistance (of thermistor) decreases ; 4 current (in thermistor) increases ; reference to P = IV; power increases ; 3(c) straight line goes / through the origin; 2 Any one from: constant resistance ; current proportional to voltage ; obeys Ohm’s law ; resistance = 1 ÷ gradient ;

This question in 0654/43 Oct/Nov 2024

12 (a) Fig. 12.1 shows two identical resistors each of resistance 3.8 Ω connected to a cell. P 3.8 Ω 3.8 Ω Q Fig. 12.1 (i) The electromotive force (e.m.f.) of the cell is 1.5 V. Define e.m.f. … … [2] (ii) State the potential difference (p.d.) between points P and Q. State the unit of your answer. p.d. = … unit … [2] (iii) Calculate the combined resistance of the two resistors. resistance = … Ω [1] (b) Fig. 12.2 shows a piece of metal wire with a resistance of 40 Ω along its length. length cross-sectional area Fig. 12.2 A potential difference is applied across the ends of the wire. Describe the process of electrical conduction in the wire. … … … … … [3] (c) A second piece of wire of the same material and length as in Fig. 12.2 has double the diameter. (i) Circle the change, if any, to the cross-sectional area of the wire. halved no change doubled multiplied by 4 [1] (ii) Determine the resistance of this piece of wire. resistance = … Ω [1] [Total: 10]

10 marks

Mark scheme: 12(a)(i) (electrical) work done / energy transferred (by a source); 2 moving a unit charge around a complete/whole circuit; 12(a)(ii) 0.75; 2 V; 12(a)(iii) 7.6 () 1 12(b) delocalised electrons; 3 (electrons) move / flow; from negative potential to positive potential; 12(c)(i) multiplied by 4; 1 12(c)(ii) 10 (); 1

This question in 0654/43 May/June 2025

12 (a) (i) Describe the construction of a step-up transformer. You may wish to draw a labelled diagram. … … … [2] (ii) A step-up transformer reduces the current in an electricity transmission wire from 20 000 A to 500 A. Calculate the power lost in a wire with resistance 0.60 Ω when the current is 500 A. power lost = … W [2] (b) An electrical current can be either direct or alternating. State the difference between direct current (d.c.) and alternating current (a.c.). … … … [1] (c) Fig. 12.1 shows a simple a.c. generator used to produce electricity. rotating coil N magnet S slip rings brushes a.c. output Fig. 12.1 (i) Explain why slip rings are required. … … … [2] (ii) The coil in the generator is rotated at a constant speed. On Fig. 12.2 sketch a graph of e.m.f. against time for the output of the a.c. generator. e.m.f. 0 0 time Fig. 12.2 [2] (iii) The speed of rotation of the coil in the generator is doubled. Describe how the e.m.f. against time graph changes. … … … [2] [Total: 11]

11 marks

Mark scheme: 12(a)(i) primary coil with fewer turns (than secondary) / ORA ; 2 soft iron core ; 12(a)(ii) P = I²R or 500²  0.6 ; 2 150 000 (W) ; 12(b) (d.c.) electric charge (only) flows in one direction / current (only) flows in one direction 1 OR (a.c.) electric charge changes / reverses direction (periodically) / current changes / reverses direction (periodically) ; 12(c)(i) maintain a connection to each side of the coil ; 2 so wires do not twist / so wires do not tangle ; 12(c)(ii) sine wave with positive and negative e.m.f. ; 2 constant amplitude and period ; 12(c)(iii) amplitude doubles ; 2 period halves or frequency doubles ;

This question in 0654/43 Oct/Nov 2025