A 12 V battery is connected to two identical fixed resistors in series. A voltmeter across one reads 6.0 V. The resistors are then connected in parallel across the same ideal battery; their resistances do not change.
Compare the voltage across each resistor, the current in each resistor and the total battery current in the two arrangements.
[4 marks]
6 marksFoundation and Higher6.2.4.1 Power6.2.4.2 Energy transfers in everyday appliances
AQA Trilogy 8464
Spec and skills
Paper scope: P1
Spec 6.2.4.1
Spec 6.2.4.2
Original practice question
Answer and supported method checks
A 15 Ω resistor carries a current of 0.40 A for 200 s. Its resistance remains constant.
.1
Calculate the resistor's power.
[2 marks]
.2
Calculate the energy transferred in 200 s.
[2 marks]
.3
Predict and explain the effect on power of doubling current at the same resistance.
[2 marks]
5 marksFoundation and Higher6.3.2.3 Changes of state and specific latent heat6.3.2.1 Internal energy
AQA Trilogy 8464
Spec and skills
Paper scope: P1
Spec 6.3.2.3
Spec 6.3.2.1
Original practice question
Answer and supported method checks
A pure liquid cools at a steady rate of energy loss. Its temperature falls from 60 °C to 40 °C in 4 minutes, stays at 40 °C for 6 minutes, then falls below 40 °C.
024681012203040506070Time (min)Temperature (°C)
.1
Calculate the average rate of temperature decrease during the first 4 minutes, in °C per minute.
[2 marks]
.2
Explain the horizontal section and the fall afterwards on the temperature-time graph.
[3 marks]
6 marksFoundation and Higher6.4.2.3 Half-lives and the random nature of radioactive decay
AQA Trilogy 8464
Spec and skills
Paper scope: P1
Spec 6.4.2.3
Original practice question
Answer and supported method checks
A detector registers 96 counts per minute of background radiation. With a source present it registers 896 counts per minute initially and 496 counts per minute after 12 minutes.
.1
Calculate the initial corrected detected count rate in min−1 (counts per minute).
[2 marks]
.2
Determine the half-life in minutes.
[2 marks]
.3
Explain why the background must be subtracted before comparing the rates.
[2 marks]
7 marksHigher6.1.1.2 Changes in energy
AQA Trilogy 8464
Spec and skills
Paper scope: P1
Spec 6.1.1.2
Original practice question
Answer and supported method checks
A spring stores 0.72 J when compressed by 0.060 m. It obeys Hooke's law throughout this compression. It launches an initially stationary 0.090 kg toy horizontally; 25% of the stored energy is dissipated.
.1
Calculate the spring constant.
[2 marks]
.2
Calculate the toy's speed when it leaves the spring.
[3 marks]
.3
Explain why the speed cannot be found by treating the dissipated energy as destroyed.
