The maximum induced emf in a generator whose coils are rotating at 240 rpm is 35 V.If,instead,it is desired to generate a maximum emf of 45 V but with half the magnetic field,what rotation rate must be used?
A) 380 rpm
B) 190 rpm
C) 310 rpm
D) 165 rpm
E) 610 rpm

Question

Quizplus · Accepted Answer

The induced emf is proportional to the product of the magnetic field strength, the number of turns, and the angular velocity. If the magnetic field is halved, the angular velocity must be doubled to achieve the same emf. To increase the emf from 35 V to 45 V, the angular velocity must be increased further. Therefore, the new rotation rate is calculated as (240 rpm * 2 * (45/35)) = 610 rpm.

The Maximum Induced Emf in a Generator Whose Coils Are