Question

A coil having 100 turns is kept in a uniform magnetic field of induction 0.5 T. If its area changes from 0.3 $m^2$ to 0.1 $m^2$ in 10 s, then the emf induced is ______V.

• A. 2
• B. 1
• C. 4
• D. 3

Answer 1

Answer: (B)

1

EMF induced is the rate of change in magnetic flux linked with a coil.

Change in magnetic flux$=\Delta \phi=N\Delta AB=100\times (0.3-0.1)\times 0.5=10Tm^2$

$emf=\frac{\Delta \varphi }{t}=\frac{10}{10}$

$emf=1V$

Answer-(B)