Question

A thin semicircular conducting the ring $\left(PQR\right)$ of radius ${}^{\prime }{r}^{\prime }$ is falling with its plane vertical in a horizontal magnetic field $B$, as shown in figure. The potential difference developed across the ring when its speed is $v$, is

• A. $Zero$
• B. $Bv\pi r^2/2$ and $P$ is at higher potential
• C. $\pi rBv$ and $R$ is at higher potential
• D. $2rBv$ and $R$ is at higher potential

Answer 1

The correct option is D $2rBv$ and $R$ is at higher potential

$emf=VB{l}_{eq}$
$=VB\left(2R\right)$

where R is at higher potential and P is at lower potential