question_answer

A non-conducting ring of radius 0.5 m carries a total charge of \[1.11\times {{10}^{-10}}C\]distributed non-uniformly on its circumference producing an electric field E everywhere in space. The value of the integral \[\int\limits_{\ell =\infty }^{\ell =0}{-E.dl}\] (\[\ell =0\]being center of the ring) in volts is

A) +2

B) -1   

C) -2

D) zero

Correct Answer: A

Solution :

[a] \[K=\frac{{{V}_{0}}}{V}-1\] \[=\frac{kq}{r}=-\,0\] \[\frac{9\times {{10}^{9}}\times 1.11\times {{10}^{-10}}}{0.5}\] \[\approx 2V\]