An electric dipole of moment → P is lying along uniform electric field. The work done in rotating the dipole by 90° is :
- \(\sqrt 2pE\)
- \(\frac{pE}{2}\)
- 2pE
- pE
The Correct Option is D
Solution and Explanation
A torque = pE acts on an electric dipole when it is positioned in an electric field E.
The dipole is being rotated via an angle by this torque.
Work done by an external force is provided by if the dipole is rotated from angle 1 to 2.
W=pE (cos 1+cos 2)
(i) When we enter 1= 0° and 2 = 90° in Eq. (i), we obtain W=pE (cos0°cos90°)= pE(10) =pE.
Therefore, the correct option is (D): pE
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Concepts Used:
Electric Field
Electric Field is the electric force experienced by a unit charge.
The electric force is calculated using the coulomb's law, whose formula is:
\(F=k\dfrac{|q_{1}q_{2}|}{r^{2}}\)
While substituting q2 as 1, electric field becomes:
\(E=k\dfrac{|q_{1}|}{r^{2}}\)
SI unit of Electric Field is V/m (Volt per meter).