(a) To increase the output of an ac generator, a student has the choice of doubling either the generator’s magnetic field or its frequency. To maximize the increase in emf output, (1) he should double the magnetic field, (2) he should double the frequency, (3) it does not matter which one he doubles. Explain.
(b) Two students display their ac generators at a science fair. The generator made by student A has a loop area of 100 cm2 rotating in a magnetic field of 20 mT at 60 Hz. The one made by student B has a loop area of 75 cm2 rotating in a magnetic field of 200 mT at 120 Hz. Which one generates the largest maximum emf? Justify your answer mathematically.