An electric dipole of moment $straight P with rightwards arrow on top$ is lying along a uniform electric field $straight E with rightwards arrow on top.$ The work done in rotating the dipole by $90 degree$

$square root of 2 pE$
$pE over 2$

2pE

pE

Solution

When an electric dipole in an electric field $bold E with bold rightwards arrow on top bold comma$ a torque $straight t with rightwards arrow on top space equals space straight rho with rightwards arrow on top space cross times space straight E with rightwards arrow on top$ acts on it. This torque tries to rotate the dipole through an angle.
If the dipole is rotated from an angle $straight theta subscript 1 space to space straight theta subscript 2$ , then work done by external force is given by
$straight W space equals space pE left parenthesis cos space straight theta subscript 1 space minus space cos space straight theta subscript 2 right parenthesis$ ...(i)
putting $straight theta subscript 1 space equals space 0 degree comma space space straight theta subscript 2 space equals space 90 degree space in space the space Eq. space left parenthesis straight i right parenthesis comma space we space get$
$straight W space equals space pE left parenthesis cos space 0 degree space minus space cos space 90 degree right parenthesis space space space space space equals space pE left parenthesis 1 minus 0 right parenthesis space space space space space equals space pE$

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Electrostatic Potential And Capacitance

An electric dipole of moment $straight P with rightwards arrow on top$ is lying along a uniform electric field $straight E with rightwards arrow on top.$ The work done in rotating the dipole by $90 degree$

$square root of 2 pE$
$pE over 2$

2pE

pE

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Electrostatic Potential And Capacitance

An electric dipole of moment is lying along a uniform electric field The work done in rotating the dipole by 2pE pE

Some More Questions From Electrostatic Potential and Capacitance Chapter

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

An electric dipole of moment $straight P with rightwards arrow on top$ is lying along a uniform electric field $straight E with rightwards arrow on top.$ The work done in rotating the dipole by $90 degree$

$square root of 2 pE$
$pE over 2$

2pE

pE