An electric dipole of dipole moment `4xx10^(-5)` Cm is placed in a uniform electric field of `10^(-3) N//C` making an angle of `30^(@)` with the direction of the field. Determine the torque exerted by the electric field on the dipole.

Options

A. `7 . 7 xx 10^(-13) ` Nm
B. `3 . 855 xx 10^(-13) ` Nm
C. `3 .855 xx 10^(-15) ` Nm
D. `7 . 7 xx 10^(-15)` Nm

Answer

B

Explanation

`tau = ( 2 . 57 xx 10 ^(-17) Cm) (3 . 0 xx 10^(4) (N)/(C)) ((1)/(2))`
`= 3 . 855 xx 10^(-13) Nm`