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A hybrid car has an electric motor and a petrol engine - AQA - GCSE Physics Combined Science - Question 3 - 2019 - Paper 1
Question 3
A hybrid car has an electric motor and a petrol engine. Petrol is a non-renewable energy resource. What is meant by a non-renewable energy resource? [1 mark] ____... show full transcript
Worked Solution & Example Answer:A hybrid car has an electric motor and a petrol engine - AQA - GCSE Physics Combined Science - Question 3 - 2019 - Paper 1
Step 1
Step 2
Calculate the current used to charge the battery.
Answer
To find the current, we can use the formula for power:
Where:
- P is the power in watts (W)
- V is the voltage in volts (V)
- I is the current in amperes (A)
Given:
- Power, P = 6.9 kW = 6900 W
- Voltage, V = 230 V
Rearranging the formula to find current:
Substituting the values:
Calculating gives:
Step 3
Explain the difference between direct and alternating potential difference.
Answer
Direct potential difference (DC) is a constant flow of electric charge in one direction, meaning the current always travels in the same direction. In contrast, alternating potential difference (AC) involves changing directions, where the current alternates its path periodically.
Step 4
Explain why it is better to use a cable with a low resistance than to use a cable with a high resistance.
Answer
Using a cable with a low resistance minimizes power loss as heat, allowing for more efficient energy transfer from the mains supply to the battery. A low-resistance cable reduces the energy dissipation, hence the battery charges faster and remains cooler compared to a high-resistance cable.