This question is about using the mains electricity supply - Edexcel - GCSE Physics Combined Science - Question 3 - 2021 - Paper 1

To calculate the energy transferred to the coffee machine, we will use the formula:

$E = I \times V \times t$

Where:

• I = 7.4 A
• V = 230 V
• t = 120 s

Substituting the values:

$E = 7.4 \times 230 \times 120$

Calculating this gives:

$E = 204000 J$

Therefore, the energy transferred to the coffee machine is 204,000 J.

Wire X is the earth wire. Wire Y is the live wire.

Component Z is a fuse.

To find the input current, use the equation related to the transformer:

$\text{input current} \times \text{input voltage} = \text{output current} \times \text{output voltage}$

Rearranging the formula for input current gives:

$\text{input current} = \frac{\text{output current} \times \text{output voltage}}{\text{input voltage}}$

Substituting in the values:

• Output current = 2.37 A
• Output voltage = 190 V
• Input voltage = 230 V

Thus:

$\text{input current} = \frac{2.37 \times 190}{230}$

Calculating this:

$\text{input current} \approx 0.196 A$

Therefore, the input current to the transformer is approximately 0.196 A.