Power and efficiency: OCR GCSE Combined Science A questions

Every OCR GCSE Combined Science A exam question on P5.2 Power and efficiency, 2018–2025, with its mark scheme and examiner’s report.

All 83 questions on Power and efficiency, as a list

June 2025, Physics Paper 5 Foundation, Q10 (1 mark): A builder carries bricks to the top of the same ladder on four mornings. All the bricks have the same mass. On which morning does the builder use the most power
June 2025, Physics Paper 6 Foundation, Q14(a)(iii) (1 mark): Explain why the actual amount of thermal energy needed to raise the temperature of the water would be greater than the calculated value in (a)(ii). [1]
June 2025, Physics Paper 6 Foundation, Q14(b)(i) (1 mark): What is the time taken for the temperature of the water in cup B to decrease from 80 °C to 60 °C? Time taken = minutes [1]
June 2025, Physics Paper 6 Foundation, Q14(b)(ii) (2 marks): One cup is made of metal and the other cup is made of plastic. The metal cup is a better conductor than the plastic cup. Which cup, A or B, is made of metal? Gi
June 2025, Physics Paper 6 Foundation, Q14(b)(iii) (2 marks): Suggest two variables the students should control in their experiment. 1 2 [2]
June 2025, Physics Paper 6 Foundation, Q14(b)(iv) (2 marks): The students wrap the cups in thermal insulation and repeat the same experiment, as shown in the diagram. Thermometer Hot water Thermal insulation Cup A Cup B P
June 2025, Physics Paper 12 Higher, Q5 (1 mark): Which of these would not reduce unwanted energy transfers? A Filling gaps around doors and window frames B Lubricating a bicycle chain C Increasing the temperat
June 2024, Physics Paper 5 Foundation, Q13(d) (2 marks): The heater is turned on for 150 seconds. The power of the heater is 15 W. Calculate the energy transferred by the heater. Use the equation: energy transferred =
June 2024, Physics Paper 5 Foundation, Q16(b) (3 marks): This is the data from student Q: • Work done = 36 000 J • Time taken = 240 s Calculate the power of student Q. Use the equation: power = work done time Give you
June 2024, Physics Paper 5 Foundation, Q16(c) (3 marks): Describe how the students carry out this experiment. Include any equipment they use. [3]
June 2024, Physics Paper 5 Foundation, Q16(d)(i) (1 mark): How can student P’s results be described? Tick one (3) box in each row. Yes No Precise Repeatable [1]
June 2024, Physics Paper 5 Foundation, Q16(d)(ii) (2 marks): Explain your answer to (d)(i). [2]
June 2024, Physics Paper 6 Foundation, Q5 (1 mark): Material X has a high thermal conductivity. Material Y has a low thermal conductivity. Each material is wrapped around a different identical beaker containing w
June 2024, Physics Paper 6 Foundation, Q16(c) (2 marks): A 2.4 kW heater is used for 2.5 hours each day for 1 week. Calculate the energy transferred in kW h by the heater in 1 week. Use the equation: energy transferre
June 2024, Physics Paper 11 Higher, Q11(b) (3 marks): This is the data from student Q: • Work done = 36 000 J • Time taken = 240 s Calculate the power of student Q. Use the equation: power = work done time Give you
June 2024, Physics Paper 11 Higher, Q11(c) (3 marks): Describe how the students carry out this experiment. Include any equipment they need to use. [3]
June 2024, Physics Paper 11 Higher, Q11(d)(i) (1 mark): How can student P’s results be described? Tick one (3) box in each row. Yes No Precise Repeatable [1]
June 2024, Physics Paper 11 Higher, Q11(d)(ii) (2 marks): Explain your answer to (d)(i). [2]
June 2024, Physics Paper 12 Higher, Q5 (1 mark): In energy transfers, some energy is dissipated. Into which store does the dissipated energy go? A A chemical store B A gravitational store C A nuclear store D A
June 2024, Physics Paper 12 Higher, Q7 (1 mark): How can a house be heated more efficiently? A Increase the temperature in the house. B Turn the radiators on for a longer time. C Use insulation with a greater
June 2024, Physics Paper 12 Higher, Q11(c) (2 marks): A 2.4 kW heater is used for 2.5 hours each day for 1 week. Calculate the energy transferred in kW h by the heater in 1 week. Use the equation: energy transferre
June 2023, Physics Paper 5 Foundation, Q12(c) (2 marks): The student repeats the experiment. They say that the energy transferred by the Bunsen burner is 40 000 J after 200 s. Calculate the power of the Bunsen burner.
June 2023, Physics Paper 5 Foundation, Q12(d)(i) (1 mark): The student says, ‘Bunsen burner A has the highest power.’ Explain how the graph shows this. [1]
June 2023, Physics Paper 6 Foundation, Q3 (1 mark): A student calculates the efficiency of an energy transfer. The input energy is 1600 J. The useful output energy is 1200 J. Which answer shows the correct calcul
June 2023, Physics Paper 6 Foundation, Q17(f) (3 marks): A 0.8 kW microwave oven is used to cook food. The microwave oven transfers 0.56 kWh when it is used to cook food. Calculate the time the microwave oven is used
June 2023, Physics Paper 11 Higher, Q14(e) (3 marks): Student C also repeats the experiment. They say the thermal energy transferred is 32 000 J after 200 s. Use student C’s value to calculate the power of the Buns
June 2023, Physics Paper 11 Higher, Q16(b)(i) (2 marks): The kinetic energy of the marble at the bottom of the track is less than the potential energy of the marble calculated at the top of the track. Suggest and expl
June 2023, Physics Paper 12 Higher, Q12(f) (3 marks): A 0.8 kW microwave oven is used to cook food. The microwave oven transfers 0.56 kWh when it is used to cook food. Calculate the time the microwave oven is used
June 2022, Physics Paper 5 Foundation, Q1 (1 mark): Four weightlifters A, B, C and D, each do 2000 J of work lifting a weight. The time taken for each of them to do their lift is shown in the graph. 5.0 4.0 3.0 T
June 2022, Physics Paper 6 Foundation, Q12(b)(i) (1 mark): An electric shower has a power of 8.5 kW. 1 kW = 1000 W. What is the power of the shower in watts (W)? Power = W [1]
June 2022, Physics Paper 6 Foundation, Q12(b)(ii) (1 mark): The graph shows the relationship between energy transfer in kJ and energy transfer in kWh. 0.6 0.5 0.4 Energy transfer 0.3 (kWh) 0.2 0.1 0.0 0 500 1000 1500 200
June 2022, Physics Paper 11 Higher, Q6 (1 mark): A student does 20 “step ups” onto a wall. • The total work done by the student is 3000 J. • The time taken is 24 s. Calculate the power of the student. Use the
June 2022, Physics Paper 12 Higher, Q5 (1 mark): A filament lamp has a resistance of 1000 Ω and a current of 0.25 A. What is the power of the filament lamp? Use the equation: power = (current)2 × resistance A
June 2022, Physics Paper 12 Higher, Q10 (1 mark): The diagram shows a power station called a ‘combined heat and power’ (CHP) station. To national grid Coal CHP station Hot water piped to homes and offices Why i
June 2022, Physics Paper 12 Higher, Q13(c)(i) (4 marks): Calculate the amount of energy saved by unplugging the receiver compared to switching the receiver off for 8 hours at night. Use the Data Sheet. Give your answe
June 2022, Physics Paper 12 Higher, Q16(c)(ii) (3 marks): The potential energy of the ball at E is 0.45 J. Calculate the efficiency of the ball bounce. Use the Data Sheet and your answer to (c)(i). Efficiency = [3]
November 2021, Physics Paper 5 Foundation, Q3 (1 mark): Which statement describes power? A The rate of flow of charge. B The rate of flow of current. C The rate of stretching of a spring. D The rate of transfer of en
November 2021, Physics Paper 5 Foundation, Q13(b) (3 marks): Another teacher does 1500 J of work. They take 5 seconds to do the work. Calculate their power. Give the unit in your answer. Use the equation: power = work don
November 2021, Physics Paper 6 Foundation, Q3 (1 mark): A 2.5 kW electric radiator is used for 2 hours. Calculate the energy transferred. Use the equation: energy transferred = power × time A 1.25kWh B 5 kWh C 1250 k
November 2021, Physics Paper 6 Foundation, Q5 (1 mark): A student investigates how hot water in an insulated beaker cools. Thermometer Beaker Water Insulation Table They test how the thickness of insulation affects t
November 2021, Physics Paper 6 Foundation, Q15(c) (3 marks): A TV transmitter has a useful output energy transfer of 100 kJ in 1 second. The input energy is 250 kJ in 1 second. Calculate the efficiency of the TV transmitt
November 2021, Physics Paper 11 Higher, Q12(a) (1 mark): Explain in words what is meant by power. [1]
November 2021, Physics Paper 11 Higher, Q12(b)(ii) (4 marks): This is some data for a weightlifter. Weight lifted = 620 N Height of the lift = 1.6 m Time taken to complete lift = 4.0 s Calculate the power generated by the
November 2021, Physics Paper 12 Higher, Q5 (1 mark): A student investigates how hot water in an insulated beaker cools. They test how the thickness of insulation affects the rate of cooling. Thermometer Beaker Wat
November 2021, Physics Paper 12 Higher, Q10 (1 mark): An 800 W microwave oven is used for 30 minutes. What is the energy transferred in kWh? Use the equation: energy transferred = power × time A 0.4 kWh B 24 kWh C
November 2021, Physics Paper 12 Higher, Q11(c) (3 marks): A TV transmitter has a useful output energy transfer of 100 kJ in 1 second. The input energy is 250 kJ in 1 second. Calculate the efficiency of the TV transmitt
November 2020, Physics Paper 6 Foundation, Q5 (1 mark): A heater transfers 150 000 J of energy in 120 s. Calculate the power of the heater. Use the equation: energy transferred = power × time A 0.80 W B 1.25 W C 1250
November 2020, Physics Paper 6 Foundation, Q6 (1 mark): Which row in the table is correct? Use the equation: efficiency = useful output energy transfer / input energy transfer Useful output energy Input energy Effici
November 2020, Physics Paper 6 Foundation, Q11(b)(i) (2 marks): The student reads the meters in the circuit in Fig. 11.1. • The value of the potential difference is 230 V. • The value on the ammeter is 0.5 A. Calculate the a
November 2020, Physics Paper 6 Foundation, Q11(b)(ii) (1 mark): Another lamp has a power of 100 W. 1 kW = 1000 W What is the power of the lamp in kilowatts (kW)? Put a ring around the correct answer. 0.1 kW 1 kW 100 kW 100 0
November 2020, Physics Paper 6 Foundation, Q11(c) (1 mark): Suggest how the student can make his readings more precise. [1]
November 2020, Physics Paper 6 Foundation, Q11(d) (2 marks): Fig. 11.2 shows a night-light. It contains a 1.0 W lamp and a 3.0 V battery. The student compares the mains filament lamp with the night-light. They are both us
November 2020, Physics Paper 6 Foundation, Q16(a) (3 marks): Calculate the rate of temperature change over the 5 minutes. Rate of temperature change = °C / minute [3]
November 2020, Physics Paper 6 Foundation, Q16(b)(i) (2 marks): Describe, in detail, how the temperature changes over the 5 minutes. [2]
November 2020, Physics Paper 6 Foundation, Q16(c) (2 marks): Describe the change in energy stores as the water cools down. [2]
November 2020, Physics Paper 6 Foundation, Q16(d)(i) (1 mark): Add another line to the graph in Fig. 16.1 to show how the temperature may change when the beaker is wrapped with insulation. [1]
November 2020, Physics Paper 6 Foundation, Q16(d)(ii) (1 mark): State one thing the student can do to reduce the rate of cooling further. [1]
November 2020, Physics Paper 12 Higher, Q5 (1 mark): A student measures the energy transferred by an electrical heater. Which row in the table shows the correct apparatus he used? To measure To measure To measure
November 2020, Physics Paper 12 Higher, Q7 (1 mark): How can the efficiency of an energy transfer be increased? A Decrease the total energy input. B Decrease the wasted energy. C Increase the total energy input. D
November 2020, Physics Paper 12 Higher, Q8 (1 mark): A 1500 W heater is used for 1.5 hours. What is the energy transferred in kWh? Use the equation: energy transferred = power × time A 2.25 kWh B 135 kWh C 2250 kW
November 2020, Physics Paper 12 Higher, Q11(a) (3 marks): Calculate the rate of temperature change over the 5 minutes. Rate of temperature change = °C / minute [3]
November 2020, Physics Paper 12 Higher, Q11(b)(i) (2 marks): Describe, in detail, how the temperature changes over the 5 minutes. [2]
November 2020, Physics Paper 12 Higher, Q11(c) (2 marks): Describe the change in energy stores as the water cools down. [2]
November 2020, Physics Paper 12 Higher, Q11(d)(i) (1 mark): Add another line to the graph in Fig. 11.1 to show how the temperature may change when the beaker is wrapped with insulation. [1]
November 2020, Physics Paper 12 Higher, Q11(d)(ii) (1 mark): State one thing the student can do to reduce the rate of cooling further. [1]
June 2019, Physics Paper 5 Foundation, Q6 (1 mark): Which row of the table gives a power of 300 W? Use the equation: power = work done ÷ time Work done (J) Time taken (s) A 600 1.5 B 900 3.0 C 1000 5.0 D 1500 300
June 2019, Physics Paper 6 Foundation, Q6 (1 mark): A 30 kW boiler is used for 4 hours. Calculate the energy transferred. Use the equation: energy transferred = power × time A 7.5 kWh B 120 kWh C 7500 kWh D 120 0
June 2019, Physics Paper 6 Foundation, Q8 (1 mark): Calculate the efficiency of this light bulb. Use the equation: efficiency = useful output energy transfer ÷ input energy transfer 180 J wasted 20 J useful outpu
June 2019, Physics Paper 6 Foundation, Q14(a)(ii) (1 mark): Describe how energy is dissipated in the electric fan. [1]
June 2019, Physics Paper 6 Foundation, Q14(a)(iii) (2 marks): The electric fan is rated 230 V, 0.3 A. Calculate the power of the electric fan. Use the equation: power = potential difference × current Power = W [2]
June 2019, Physics Paper 12 Higher, Q7 (1 mark): For how long can you use a 2 kW electrical heater with 1 kWh of energy? A 0.0005 hours B 0.5 hours C 2 hours D 2000 hours Your answer [1]
June 2018, Physics Paper 5 Foundation, Q6 (1 mark): Which of the following transfers the most energy? A 1.0 kW over one hour B 2.0 kW over two hours C 3.0 kW over one hour D 500 W over four hours Your answer [1]
June 2018, Physics Paper 5 Foundation, Q16(a)(ii) (4 marks): Calculate the power of the motor if the car takes 5.0 seconds to travel the 1.0 m distance. State the unit. Answer = Unit [4]
June 2018, Physics Paper 6 Foundation, Q4 (1 mark): Energy is transferred when a machine is switched on. • 1000 J is the input energy transfer • 750 J is useful output energy transfer Use the equation: Efficiency
June 2018, Physics Paper 6 Foundation, Q12(b) (3 marks): The kettle is switched on for 60 seconds. Calculate the energy transferred. Answer = J [3]
June 2018, Physics Paper 6 Foundation, Q12(c)(i) (1 mark): A hairdryer has a power of 1800 W. What is the power of the hairdryer in kilowatts (kW)? Answer = kW [1]
June 2018, Physics Paper 6 Foundation, Q14(b)(i) (1 mark): Explain how the scientist could reduce energy transfer to the surroundings. [1]
June 2018, Physics Paper 6 Foundation, Q14(d)(i) (2 marks): The current through the heater is 3.8 A. The potential difference across the heater is 9.0 V. Use the equation: Power = Potential difference × Current Calculate
June 2018, Physics Paper 11 Higher, Q11(a)(ii) (4 marks): Calculate the power of the motor if the car takes 5.0 seconds to travel the 1.0 m distance. State the unit. Answer = Unit [4]
June 2018, Physics Paper 11 Higher, Q11(c) (1 mark): The student wishes to increase the time taken to lift this toy car vertically through the 1.0 m distance shown. Suggest a change he could make to this experimen
June 2018, Physics Paper 11 Higher, Q16(c) (3 marks): At 10 °C the thermistor had a resistance of 1900 Ω. The thermistor has a power rating of 75 × 10–3 W. Calculate the maximum current in this thermistor at 10 °C.
June 2018, Physics Paper 12 Higher, Q10 (1 mark): A teacher adds 200 cm3 of warm water to a beaker. He wraps the beaker in insulation. He measures the temperature drop after 10 minutes. The table shows the resu
June 2018, Physics Paper 12 Higher, Q15(b) (4 marks): The security light is switched on for 45 minutes every day for 7 days. Use the equation: Energy transferred = Power × Time Calculate the energy transferred in k

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