a semicircle wire of radius `R` is rotated with constant angular velocity about an axis passing through one end and perpendicular to the plane of wire. There is a uniform magnetic field of strength `B`. The induced emf between the ends is

Options

A. (a) `BomegaR^(2)//2`
B. (b) `2BomegaR^(2)`
C. ( c) is variable
D. (d) none of these

Answer

B

Explanation

(b) We connect a conducting wire from `A` to `C` and complete the semicircular loop.
The emf in the semicircular loop is zero because its magnetic flux does not change.
`:.` Emf of section `APC + emf of section CQA = 0`
`:.` Emf of section `APC = emf of section AQC = 2BR^(2) omega`