A short electric dipole has a dipole moment of 16 × 10^−9Cm. The electric potential due to the dipole at a point at a distance of 0.6 m from the centre of the dipole, situated on a line making an angle of 60◦ with the dipole axis is ?

A short electric dipole has a dipole moment of 16 × 10^−9Cm. The electric potential due to the dipole at a point at a distance of 0.6 m from the centre of the dipole, situated on a line making an angle of 60◦ with the dipole axis is ?

\( \frac{1}{4\pi\varepsilon_0} = 9 \times 10^9 \ \text{N·m}^2/\text{C}^2 \)

(a) 200 V

(b) 400 V

(c) 0 V

(d) 50 V

Answer :  (a) 200 V

\( p = 2q\ell = 16 \times 10^{-9} \)

\( V = \frac{k \cdot p \cdot \cos \theta}{r^2} \)

\( = \frac{9 \times 10^9 \times 16 \times 10^{-9} \times \cos 60^\circ}{(0.6)^2} \)

\( = \frac{9 \times 16 \times \frac{1}{2}}{6 \times 6 \times \frac{1}{10}} \times 10^2 \)

\( = 2 \times 10^2 \)