An electric dipole of length 1 cm is placed with the axis making an angle of 30o to an electric field of strength 104NC-1 . If it experiences a torque of 10√2Nm, the potential energy of the dipole is

Question

An electric dipole of length 1 cm is placed with the axis making an angle of 30o to an electric field of strength 104NC-1 . If it experiences a torque of 10√2Nm, the potential energy of the dipole is (A)  0.245 text J  (B)  2.45× 10-4J  (C)  0.0245 text J  (D)  245.0 text J

Tardigrade Admin · Accepted Answer

Torque, τ =pE sin θ or P=(τ /E sin θ ) Potential energy, U=pE cos θ =(τ /E sin θ ).E cos θ =(τ /E tan θ )=(10√2/104 tan 30o) =24.5× 10-4J

Q. An electric dipole of length $1 c m$ is placed with the axis making an angle of $30^{o}$ to an electric field of strength $10^{4} N C^{- 1}$ . If it experiences a torque of $102 N m,$ the potential energy of the dipole is

$0.245 J$

$2.45 \times 10^{- 4} J$

$0.0245 J$

$245.0 J$

$24.5 \times 10^{- 4} J$

Torque, $τ = pE sin θ$ or $P = \frac{τ}{E s i n θ}$
Potential energy, $U = pE cos θ$
$= \frac{τ}{E s i n θ} . E cos θ$
$= \frac{τ}{E t a n θ} = \frac{10 2}{10 ^{4} t a n 30 ^{o}}$
$= 24.5 \times 10^{- 4} J$

Q. An electric dipole of length 1cm is placed with the axis making an angle of 30o to an electric field of strength 104NC−1 . If it experiences a torque of 102​Nm, the potential energy of the dipole is

0.245J

2.45×10−4J

0.0245J

245.0J

24.5×10−4J

Torque, τ=pEsinθ or P=Esinθτ​ Potential energy, U=pEcosθ =Esinθτ​.Ecosθ =Etanθτ​=104tan30o102​​ =24.5×10−4J