Electrostatics Question 318
Question: Two charges $ +3.2\times {{10}^{-19}}C $ and $ -3.2\times {{10}^{-9}}C $ kept 2.4 Å apart forms a dipole. If it is kept in uniform electric field of intensity $ 4\times 10^{5}volt/m $ then what will be its electrical energy in equilibrium [MP PMT 2003]
Options:
A) $ +3\times {{10}^{-23}}J $
B) $ -3\times {{10}^{-23}}J $
C) $ -6\times {{10}^{-23}}J $
D) $ -2\times {{10}^{-23}}J $
Show Answer
Answer:
Correct Answer: B
Solution:
Potential energy of electric dipole $ U=-pE\cos \theta $
$ =-(q\times 2l)E\cos \theta $
$ U=-(3.2\times {{10}^{-19}}\times 2.4\times {{10}^{-10}})4\times 10^{5}\cos \theta $
$ U=-3\times {{10}^{-23}} $ (approx.)
