A circular ring of radius r is placed in a homogeneous magnetic field perendicular to the plane of the ring. The field B changes with time according to the equation B=kt where K is constant and r is the time. The electric field in the ring is:

Options

A. `(Kr)/(4)`
B. `(Kr)/(3)`
C. `(Kr)/(2)`
D. `(K)/(2r)`

Answer

c

Explanation

`oint vecE d vecI=-(dphi_(B))/(dt)`
or `E2 pir =(d)/(dt)(Ktxxpir^(2))`
or `E=(Kr)/(2)`