Electrostatics Question 314
Question: A molecule with a dipole moment p is placed in an electric field of strength E. Initially the dipole is aligned parallel to the field. If the dipole is to be rotated to be anti-parallel to the field, the work required to be done by an external agency is [UPSEAT 2004]
Options:
A) ? 2pE
B) ? pE
C) pE
D) 2pE
Show Answer
Answer:
Correct Answer: D
Solution:
$ W=PE(1-\cos \theta ) $ here $ \theta =\text{18}{{0}^{\text{o}}} $
$ \therefore $ W = $ PE(1-\cos 180^{o}) $ = $ PE[1-(-1)]=2PE $
