Question

A metal strip $6.50\text{cm}$ long, $0.85\text{cm}$ wide moves with constant velocity $\overrightarrow{v}$ through a uniform magnetic field $B=1.20\text{mT}$, directed perpendicular to the strip, as shown in the figure. A potential difference of $3.90\mu \text{V}$ is measured between points $x$ and $y$ across the strip. Calculate the speed $v$.

• A. $2.5\text{m/s}$
• B. $5.5\text{m/s}$
• C. $1.4\text{m/s}$
• D. $0.4\text{m/s}$

Answer 1

The correct option is D $0.4\text{m/s}$

We know that, induced emf,
$e=Bvl$

$\Rightarrow 3.90\times {10}^{-6}=1.20\times {10}^{-3}\times v\times 0.85\times {10}^{-2}$

$\Rightarrow v=0.4\text{m/s}$