Electrostatics Question 218
Question: The charges on two sphere are$ +7\mu C $ and $ -5\mu C $ respectively. They experience a force F. If each of them is given and additional charge of $ -2\mu C $ , the new force of attraction will be [RPET 2002]
Options:
A) F
B) F / 2
C) $ F/\sqrt{3} $
D) 2F
Show Answer
Answer:
Correct Answer: A
Solution:
$ F=\frac{1}{4\pi {\varepsilon _{0}}}\frac{(+7\times {{10}^{-6}})(-5\times {{10}^{-6}})}{r^{2}}=-\frac{1}{4\pi {\varepsilon _{0}}}\frac{35\times 10^{12}}{r^{2}}N $
$ F’=\frac{1}{4\pi {\varepsilon _{0}}}\frac{(+5\times {{10}^{-6}})(-7\times {{10}^{-6}})}{r^{2}}=-\frac{1}{4\pi {\varepsilon _{0}}}\frac{35\times 10^{12}}{r^{2}}N $
