An electric dipole when held at 30^{\circ} with respect to a uniform electric field of 10^{4} \mathrm{~N} / \mathrm{C} experiences a torque of 9 \times 10^{-26} \mathrm{Nm}. Calculate dipole moment of the dipole?
An electric dipole when held at 30^{\circ} with respect to a uniform electric field of 10^{4} \mathrm{~N} / \mathrm{C} experiences a torque of 9 \times 10^{-26} \mathrm{Nm}. Calculate dipole moment of the dipole?

Ans: It is given that

    \[\begin{array}{l} \theta=30^{\circ} \\ \tau=9 \times 10^{-26} \mathrm{Nm} \\ E=10^{4} \mathrm{~N} / \mathrm{C} \end{array}\]

Dipole moment P needs to be calculated.
It is known that torque is given by \tau= PEsin \theta.
Clearly,

    \[\begin{array}{l} \Rightarrow P=\frac{\tau}{E \sin \theta} \\ \Rightarrow P=\frac{9 \times 10^{-25}}{10^{4} \times \sin 30^{\circ}}=\frac{9 \times 10^{-25} \times 10^{-4} \times 2}{1} \\ \Rightarrow P=18 \times 10^{-00} \mathrm{Cm} \end{array}\]