Question

An electrtic dipole with dipole moment `4xx10^(-9) C m` is aligned at `30^(@)` with the direction of a uniform electric field of magnitude `5xx10^(4) NC^(-1)`. Calculate the magnitude of the torque acting on the dipole .

Answer 1

Electric dipole moment, `p = 4 × 10^(−9) C m`
Angle made by p with a uniform electric field, `theta = 30^(@)`
Electric field,` E = 5 × 10^(4) N C^(−1)`
Torque acting on the dipole is given by the relation,
`T = pE sin theta`
`= 4 xx 10^(-9) xx 5 xx10 ^(4) xx sin 30`
`= 20 xx 10 ^(-5) xx (1)//(2)`
`=10^(-4) Nm`
Therefore, the magnitude of the torque acting on the dipole is `10^(−4) N m`.