Question

For a dipole $q=2\times 10^{- 6}C;d=0.01m;$ find the maximum torque on the dipole if $E=5\times 10^{5}NC^{- 1}$ :-

• A. $1\times 10^{- 3}Nm^{- 1}$
• B. $10\times 10^{- 3}Nm^{- 1}$
• C. $10\times 10^{- 3}Nm$
• D. $1\times 10^{- 4}Nm$

Answer 1

Answer: (C)

$\overset{ \rightarrow }{\tau}=\overset{ \rightarrow }{P} \times \overset{ \rightarrow }{E} , \left(\overset{ \rightarrow }{P}\right) = q d$
$\tau_{max}=P\cdot E=qdE$
$\tau_{max}=2\times 10^{- 6}\times 0.01\times 5\times 10^{5}$
$=10\times 10^{- 3}Nm$