Electrostatics Question 762
Question: In moving from A to B along an electric field line, the work done by the electric field on an electron is $ 6.4\times {{10}^{-19}}J. $ If $ {\phi _{1}} $ and $ {\phi _{2}} $ are equipotential surfaces, then the potential difference $ V _{C}-V _{A} $ is
Options:
A) -4V
B) 4V
C) zero
D) 6.4V
Show Answer
Answer:
Correct Answer: B
Solution:
[b] $ {W _{el.}}=q(V _{i}-V _{f}) $
or $ 6.4\times {{10}^{-19}}=-1.6\times {{10}^{-19}}( V _{A}-V _{B} ) $
or $ V _{A}-V _{B}=-4V $ or $ V _{A}-V _{C}=-4V\text{ }( \because V _{B}=V _{C} ) $
or $ V _{C}-V _{A}=4V $
