CBSE Class 12 Physics 2014 Delhi Set 2 Paper

© examsnet.com
Question : 3
Total: 8
An electric dipole of length 2‌cm, when placed with its axis making an angle of 60∘ with a uniform electric field, experiences a torque of 8√3‌Nm. Calculate the potential energy of the dipole, if it has a charge of ±4‌nC.
Solution:  
τ‌=pEsin‌θ
8√3‌=pEsin‌θ
pE‌
√3
2
‌
=8√3

So, pE=16
Potential energy of the dipole
‌=−pE‌cos‌θ
U‌=−pE‌cos‌60
U‌=−16×0.5
U‌=−8J
© examsnet.com
Go to Question: