A thin semicircular conducting ring of radius `R` is falling with its plane verticle in a horizontal magnetic inducting `B`. At the position `MNQ`, the speed of the ring is `V` and the potential difference developed across the ring is

Options

A. zero
B. `1//2BvpiR^(2)` , and `M` is at a higher potential
C. `piRBv` , and `Q` is at a higher potential
D. `2RBv` , and `Q` is at a higher potential

Answer

D

Explanation

`e=B.v2R=2BvR`
`V_(Q)-V_(M)=2BvR` .