Figure 1 shows how the National Grid connects a power station to consumers. Use the physics equations sheet to answer questions 0.1.2 and 0.1.3. Which equation links current (I), power (P) and resistance (R)? Tick (✓) one box. - P = I / R - P = I / R² - P = I² R - P = IR A transmission cable has a power loss of 1.60 × 10⁹ W. The current in the cable is 2000 A. Calculate the resistance of the cable. Resistance = _________________ Ω Write down the equation which links efficiency, total energy input and useful energy output. The total energy input to the National Grid from one power station is 34.2 GJ. The National Grid has an efficiency of 0.992. Calculate the useful energy output from this power station to consumers in GJ.

GCSE AQA Physics Energy Transfers: Figure 1 shows how the National

Figure 1 shows how the National Grid connects a power station to consumers - AQA - GCSE Physics - Question 1 - 2023 - Paper 1

Question 1

Figure 1 shows how the National Grid connects a power station to consumers. Use the physics equations sheet to answer questions 0.1.2 and 0.1.3. Which equation lin... show full transcript

Worked Solution & Example Answer:Figure 1 shows how the National Grid connects a power station to consumers - AQA - GCSE Physics - Question 1 - 2023 - Paper 1

Step 1

Which equation links current (I), power (P) and resistance (R)?

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Answer

The correct equation is $P = IR$ . This relates power (P), current (I), and resistance (R) in electrical circuits.

Step 2

Calculate the resistance of the cable.

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Answer

To find the resistance (R), we use the formula for power loss:

P = I^2 R

Rearranging gives:

R = \frac{P}{I^2}

Substituting the values:

R = \frac{1.60 \times 10^9}{2000^2} = 400 \; \Omega

Step 3

Write down the equation which links efficiency, total energy input and useful energy output.

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Answer

The equation is:

\text{efficiency} = \frac{\text{useful energy output}}{\text{total energy input}}

Step 4

Calculate the useful energy output from this power station to consumers in GJ.

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Answer

Using the efficiency equation:

\text{useful energy output} = \text{efficiency} \times \text{total energy input}

Substituting the values:

\text{useful energy output} = 0.992 \times 34.2 = 33.9 \; \text{GJ}

Figure 1 shows how the National Grid connects a power station to consumers - AQA - GCSE Physics - Question 1 - 2023 - Paper 1

Worked Solution & Example Answer:Figure 1 shows how the National Grid connects a power station to consumers - AQA - GCSE Physics - Question 1 - 2023 - Paper 1

Which equation links current (I), power (P) and resistance (R)?

Calculate the resistance of the cable.

Write down the equation which links efficiency, total energy input and useful energy output.

Calculate the useful energy output from this power station to consumers in GJ.

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