Hello again! Sorry for having so many questions, this paper has no solutions and just a vague marking criteria.
Again, sorry for the amount of questions! I really struggled with this paper and the solutions are not adequate. TIA
No need to be sorry! Let me give you a rundown:
1) Orientation doesn't matter, you can plug the input into the right and get the output from the left, no issue there. So the voltage jump from input to output would be 2.5x, so 10V becomes 25V. Then at 90% efficient, that is 22.5V - That is the best option to make sure you get your 22V without going ridiculously far over
2) Recall that
induced emf is proportional to the rate of change of flux. What this means, since you do 2U and will understand the terminology, is that the induced emf is proportional to the
derivative of flux. Flux is a sine curve, so we'd expect the induced emf to be a cosine curve. The answer is (B). We could do this without the knowledge of derivatives (namely that \(\frac{d}{dx}\sin{x}=\cos{x}\)), but this is way easier, since we have it in our toolbelt
3) Brutal question this one, the issue is that the voltmeter is in
series, where it is supposed to be connected in parallel. Voltmeters have a very large internal resistance (essentially an open circuit) to prevent impacting the circuit when connected in parallel. In series, pfft, you done f-ed up. The huge resistance stops any current from flowing, so while you'll register the 12V in your circuit, the circuit stops working - No current (0A on the ammeter) and no light
Hope this helps