A wire loop enclosing a semi-circle of radius Ris located on the boundary of a uniform magnetic field of induction B. At timc t = 0, the loop is set into rotation with angular velocity angular `omega` about its axis 0, coinciding with a line vector B on the boundary as shown in the figure. The emf induced in the loop is
 

Options

A. `(BR^(2))/(2)omega`
B. `BR omega`
C. `BR^(2)omega`
D. `(BR^(2))/(2omega)`

Answer

A

Explanation

Emf `" "=(d)/(dt)phi_(B)`
`=((d)/(dt)A).B`
`=((piR^(2))/(2pi//omega))B`
`=(1)/(2)BR^(2)omega`