Question

The figure shows a square loop of side $5\text{cm}$ being moved towards the right at a constant speed of $v=1\text{cm/s}$. The front edge just enters the $20\text{cm}$ wide magnetic field at $t=0$. Find the induced emf in the loop at $t=2\text{s}$.

• A. $3\times {10}^{-2}\text{V}$
• B. $2\times {10}^{-2}\text{V}$
• C. $5\times {10}^{-4}\text{V}$
• D. $3\times {10}^{-4}\text{V}$

Answer 1

The correct option is D $3\times {10}^{-4}\text{V}$

Velocity of the loop, $v=1\text{cm/s}$

Magnetic field, $B=0.6\text{T}$

At $t=2\text{s}$, the distance moved by the coil,

$d=vt=1\times 2=2\text{cm}$


Now, emf induced,

$ϵ=\frac{\Delta \varphi }{\Delta t}=\frac{0.6\times (2\times 5)\times {10}^{-4}-0}{2-0}$

$\Rightarrow ϵ=3\times {10}^{-4}\text{V}$