Figure shows an isosceles triangle wire frame with apex angle equal to `(pi)//2`. The frame starts entering into the region of uniform magnetic field B with constant velocity v at t =0. The longest side of the frame is perpendicular to the direction of velocity. If i is the intantaneous current through the frame then choose the alternative showing the correct variation of i with time.

Options

A.
B.
C.
D.

Answer

D

Explanation

`phi = BA = B[1/2 (2x)(x)]`

`phi = Bx^(2)`
`| epsilon | =(d phi)/(dt)=2Bx*v`
` I= (omega)/(R) =((2Bv)/(R))x`.