GCSE Physics - Anyone can answer this question about transformers? Watch
Got a question here. I know the first part is because the current has to be AC but the battery is DC. But the second part is really confusing. It says on the mark scheme the answer is 3A and underneath it says allow 1 mark for correct substitution i.e. 18 x 2 = 12 x I^2 but I have no idea where they got that from.
18 * 2 = 36 watts
36/12 = 3 amps