Question

A metallic rod of length l is tied to a string of length 2l and made to rotate with angular speed $\omega$ on a horizontal table with one end of the string fixed. If there is a vertical magnetic field B in the region, the emf induced across the ends of the rod is

• A. $\frac{7B\omega l^2}{2}$
• B. $\frac{3B\omega l^2}{2}$
• C. $\frac{5B\omega l^2}{2}$
• D. $\frac{4B\omega l^2}{2}$

Answer 1

The correct option is C $\frac{5B\omega l^2}{2}$


$dϵ=Bdxv$
$ϵ=B\omega {\int }_{2l}^{3l}xdx(v=x\omega )$
$ϵ=\frac{5B\omega l^2}{2}$