An electric dipole consists of two opposite charges of magnitude `q = 1xx10^(-6)C` separated by 2.0cm. The dipole is placed in an external field of `1xx10^(5) NC^(-1)`. What maximum torque does the field exert on the dipole ? How much work must an external agent do to rurn the dipole end for end, starting from position of aligment `(theta = 0^(@))` ?

Answer

`2xx10^(-3) N-m, 4xx10^(-3) J`

Explanation

`tau_(max) = pE sin 90^(@) = q (2a) E xx 1`
`= 10^(-6) (2xx10^(-2)) xx1xx10^(5) = 2xx10^(-3) N m`
Now, `phi_(1) = 0^(@), phi_(2) = 180^(@), W = ?`
Use , `W = -pE (cos theta_(2) - cos theta_(1))`