An electruc field of `300V//m` is confined to a circular area `10 cm` in diameter. If the field is increasing at the rate of `20V//m-s`, the magnitude of magnetic field at a point `15cm` from the centre of the circle will be-

Options

A. `1.85 xx 10^(-15)` T
B. `1.85 xx 10^(-16)` T
C. `1.85 xx 10^(-17)` T
D. `1.85 xx 10^(-18)` T

Answer

D

Explanation

`i=(pi r^(2) (dE)/(dt))epsilon_(0)`
B = `(mu_(0)i)/(2 pi r )`