An electric dipole of length 4 cm, when placed with its axis making an angle of 60° with a uniform electric field, experiences a torque of 4 square root of 3 Nm. Calculate the potential energy of the dipole, if it has charge ±8 nC - Physics

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An electric dipole of length 4 cm, when placed with its axis making an angle of 60° with a uniform electric field, experiences a torque of `4sqrt3`Nm. Calculate the potential energy of the dipole, if it has charge ±8 nC

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Solution

Torque, τ=PEsinθ=(Ql)Esinθ    ...(1)

Here, l is the length of the dipole, Q is the charge and E is the electric field.

Potential energy, U=PEcosθ=(Ql)Ecosθ    ...(2)

Dividing (2) by (1):

`T/U=((Ql)Esintheta)/(-(Ql)Ecostheta)=-tantheta`

`=>U=-T/(tantheta)`

`=>U=-T/(tan60^@)`

`=>U=(-4sqrt3)/sqrt3`

U=4 J

Concept: Electric Dipole
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2013-2014 (March) Delhi Set 1

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