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

To calculate the energy transferred, we use the formula:

$E = V \times I \times t$

Where:

• $V = 230 \text{ V}$
• $I = 7.4 \text{ A}$
• $t = 120 \text{ s}$

Substituting the values in, we find:

$E = 230 \times 7.4 \times 120 = 2,032,800 \text{ J}$

Therefore, the energy transferred to the coffee machine is 2,032,800 J.

Wire X is earth and wire Y is live.

Component Z is a fuse.

To find the input current, we rearrange the equation:

$input \, current \times input \, voltage = output \, current \times output \, voltage$

So we rearrange to:

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

Substituting the values:

$input \, current = \frac{2.37 \times 190}{230} \approx 0.196 \text{ A}$

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