An electric dipole is placed at an angle of 30º with an electric field intensity 2 ×105 N / C. It experiences a torque equal to 4 N m. The charge on the dipole, if the dipole length is 2 cm, is
7 μC
8 mC
2 mC
5 mC
Explanation:
τ = PE sin θ
4 = P × 2 × 105 × $\dfrac{1}{2}$
P = 4 × 10–5 cm = q × 2 × 10–2
So, q = $\dfrac{4 \times 10^{–5}}{2 \times 10^{–2}}$ = 2 × 10–3 coulomb
