Electrostatics Question 718
Question: A ring of charge with radius 0.5 m has $ 0.002\pi m $ gap. If the ring carries a charge of +1 C, the electric field at the center is
Options:
A) $ 7.5\times 10^{7}N{{C}^{-1}} $
B) $ 7.2\times 10^{7}N{{C}^{-1}} $
C) $ 6.2\times 10^{7}N{{C}^{-1}} $
D) $ 6.5\times 10^{7}N{{C}^{-1}} $
Show Answer
Answer:
Correct Answer: B
Solution:
[b] Charge on the element opposite to the gap is $ dq=\frac{Q}{2\pi r}( 0.002\pi ) $
$ =\frac{1}{2\pi ( 0.5 )}\times \frac{2\pi }{1000}=2\times {{10}^{-3}}C $
$ E=\frac{9\times 10^{9}\times 2\times {{10}^{-3}}}{{{( 0.5 )}^{2}}}=7.2\times 10^{7}N{{C}^{-1}} $
