AQA GCSE Physics Physics Paper 1 (Foundation), November 2021: Question 9

10 marks · Standard Demand difficulty · Short Answer

Calculate recharge times, resistance, and identify equations relating to energy, power, potential difference, current, and resistance for an electric car charging system.

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Question

Question text

09 Figure 13 shows an electric car being recharged.

Figure 13 Charging station

Power cable

09.1 The charging station applies a direct potential difference across the battery of the car.

What does ‘direct potential difference’ mean?

[1 mark]

09.2 Which equation links energy transferred (E), power (P) and time (t)?

[1 mark]

Tick ( ) one box.

power

energy transferred =

time

energy transferred =

power

energy transferred = power × time

energy transferred = power2 × time

*0339.*3 The battery in the electric car can store 162 000 000 J of energy.

The charging station has a power output of 7200 W.

Calculate the time taken to fully recharge the battery from zero.

[3 marks]

Time taken = s

09.4 Which equation links current (I), potential difference (V) and resistance (R)?

[1 mark]

Tick ( ) one box.

I = V × R

I = V 2 × R

R = I × V

V = I × R

09.5 The potential difference across the battery is 480 V.

There is a current of 15 A in the circuit connecting the battery to the motor of the

electric car.

Calculate the resistance of the motor.

[3 marks]

Resistance = Ω

09.6 Different charging systems use different electrical currents.

• Charging system A has a current of 13 A.

• Charging system B has a current of 26 A.

• The potential difference of both charging systems is 230 V.

How does the time taken to recharge a battery using charging system A compare with

the time taken using charging system B?

[1 mark]

Tick ( ) one box.

Time taken using system A is half the time of system B

Time taken using system A is the same as system B

Time taken using system A is double the time of system B

Mark scheme

Show the mark scheme

Question 9

AO /

Question Answers Extra information Mark

Spec. Ref.

the polarity (of the supply) does allow potential difference in one

09.1 1 AO1

not change direction (only)

4.2.3.1

09.2 energy transferred = power × 1 AO1

time 4.1.1.4

4.2.4.2

09.3 162 000 000 = 7200 × t 1 AO2

4.1.1.4

4.2.4.2

162 000 000 1

t =

7200

t = 22 500 (s) 1

09.4 V = I × R 1 AO1

4.2.1.3

09.5 480 = 15 × R 1 AO2

4.2.1.3

480 1

R =

R = 32 (Ω) 1

09.6 time taken using system A is 1 AO3

double the time of system B 4.2.4.1

Total 10

How to answer it

Electric Car Recharging and Circuits

What this question tests

This question assesses your knowledge of electricity and energy resources. Specifically, it tests your ability to recall and apply key equations linking energy, power, time, current, potential difference, and resistance, as well as understanding the characteristics of direct potential difference.

Part (0.1)

Meaning of Direct Potential Difference

✅ Correct Answer

The polarity (of the supply) does not change.

Accept: Potential difference in one direction (only).

💡 Key Knowledge

A direct current (d.c.) circuit or direct potential difference always flows in one direction. This is contrasted with alternating potential difference (a.c.), where the polarity continuously switches back and forth.

Part (0.2)

Equation Linking Energy, Power, and Time

✅ Correct Answer

Tick the box for: energy transferred = power × time

🧠 Exam Technique

Learn your standard equation triangles! Power is energy transferred divided by time ( P = E / t ), which rearranges to E = P × t .

Part (0.3)

Calculating Charging Time

📐 Step-by-Step Calculation

Identify equation: Energy = Power × Time ( E = P × t )
Substitute values: 162 000 000 = 7200 × t
Rearrange: t = 162 000 000 / 7200
Calculate final answer: t = 22 500 s

Marks: 3 marks total (1 for substitution, 1 for rearrangement, 1 for correct answer).

❌ Common Errors

Students often mix up multiplication and division when rearranging formulas. Always write out the formula with the numbers substituted first before rearranging to pick up method marks.

Part (0.4)

Ohm's Law Equation

✅ Correct Answer

Tick the box for: V = I × R

💡 Key Knowledge

Potential difference equals current multiplied by resistance. This is a core specification equation you must know by heart.

Part (0.5)

Calculating Motor Resistance

📐 Step-by-Step Calculation

Identify equation: Potential difference = Current × Resistance ( V = I × R )
Substitute values: 480 = 15 × R
Rearrange: R = 480 / 15
Calculate final answer: R = 32 Ω

Marks: 3 marks total (1 for correct substitution, 1 for correct rearrangement, 1 for correct unit/value).

❌ Common Errors

Don't forget to include the unit symbol (Ω) in the answer line if it isn't pre-printed. While not penalised here since Ω is provided, it is a vital habit for unstructured calculation questions.

Part (0.6)

Comparing Charging Systems

✅ Correct Answer

Tick the box for: Time taken using system A is double the time of system B

💡 Key Knowledge

System A has a current of 13 A, while System B has 26 A (double the current). Since power is proportional to current ( P = I × V ), System B delivers twice the power. Double the power means it takes half the time to transfer the same total energy, meaning System A takes double the time.

Topics

Physics · P1: Energy · P2: Electricity

Question and mark scheme from the AQA GCSE Physics examination, Physics Paper 1 (Foundation), November 2021. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.