Question

A ring of radius R has charge Q. It is cut by dl. Find the electric field at the centre-

• A. Zero
• B. $\frac{Qd\mathcal{l}}{2\pi r^{2}\varepsilon_{0}}$
• C. $\frac{Qd\mathcal{l}}{2\pi r^{3}\varepsilon_{0}}$
• D. $\frac{Qd\mathcal{l}}{8\pi^{2}\varepsilon_{0}r^{3}}$

Answer 1

Answer: (D)

$\frac{Qd\mathcal{l}}{8\pi^{2}\varepsilon_{0}r^{3}}$

Answer 2

E =; dq = $\frac { \mathrm { Qd } \ell } { 2 \pi \mathrm { r } }$