Question

A rectangular loop of length 2.5 m and width 2 m is placed at 60° to a magnetic field of 4 T. The loop is removed from the field in 10 sec. The average emf induced in the loop during this time is:

• A. -2V
• B. $+2V$
• C. $+ 1V$
• D. – 1V

Answer 1

Answer: (C)

$+ 1V$

Answer 2

The average emf induced in the loop is given by:

$\text{Average emf} = -\frac{\Delta \Phi}{\Delta t} = -\frac{0 - (4 \times (2.5 \times 2) \cos 60^\circ)}{10}$

Calculating the flux change:

$\Delta \Phi = 4 \times (2.5 \times 2) \times \frac{1}{2} = 10 \text{ Wb}$

Then,

$\text{Average emf} = -\frac{-10}{10} = +1 \text{ V}$