Question

A coil having an area of $2\, m ^{2}$ is placed in a magnetic field which changes from $1\, Wb / m ^{2}$ to $4\, Wb / m ^{2}$ in $2\, s$. The emf induced in the coil will be

• A. 4 V
• B. 3 V
• C. 2 V
• D. 1 V

Answer 1

Answer: (B)

Induced emf $e=n A \frac{d B}{d t}$
$A=$ area of coil $=2m^{2}$
and $n = 1$
$e=\frac{1 \times 2 \times(4-1)}{2}=3\, V$