Question

An electric dipole consisting of two opposite charges of $2\times {10}^{-6}C$ separated by a distance of 3cm is placed in an electric field of $2\times {10}^{5}N/C$. The maximum torque on the dipole will be

• A. $12\times {10}^{–1}Nm$
• B. $12\times {10}^{–3}Nm$
• C. $24\times {10}^{–1}Nm$
• D. $24\times {10}^{–3}Nm$

Answer 1

The correct option is B $12\times {10}^{–3}Nm$

Maximum torque = pE
$=2\times {10}^{–6}\times 3\times {10}^{–2}\times 2\times {10}^5=12\times {10}^{–3}Nm$