Question

An induced e.m.f. is produced when a magnet is plunged into a coil. The strength of the induced e.m.f. is independent of

• A. the strength of the magnet
• B. number of turns of coil
• C. the resistivity of the wire of the coil
• D. speed with which the magnet is moved

Answer 1

Answer: (C)

the resistivity of the wire of the coil

$ϵ=-\frac{Nd\varphi }{dt}\Rightarrow ϵ\propto N$ and $ϵ\propto \frac{d\varphi }{dt}$

If so the speed of magnet is fast then correspondingly rate of change of flux is fast & $ϵ$ increases. It does not depend on the resistance of coil.