Electrostatics Question 418
Question: A charged particle of mass $ 5\times {{10}^{-5}}kg $ is held stationary in space by placing it in an electric field of strength $ 10^{7}N{{C}^{-1}} $ directed vertically downwards. The charge on the particle is [EAMCET 2000]
Options:
A) $ -20\times {{10}^{-5}}\mu C $
B) $ -5\times {{10}^{-5}}\mu C $
C) $ 5\times {{10}^{-5}}\mu C $
D) $ 20\times {{10}^{-5}}\mu C $
Show Answer
Answer:
Correct Answer: B
Solution:
QE = mg $ \Rightarrow Q=\frac{mg}{E}=\frac{5\times {{10}^{-5}}\times 10}{10^{7}} $
$ =5\times 10^{5}mC $ . Since electric field is acting downward so for balance charge must be negative.
