Question

23. A ring of radius r carries a charge Q uniformly
distributed over its length. A charge q is placed
at its centre will experience a force equal to
90

a)qQ/4πɛ0r2
b)qQ/8πɛ0r3
c) Zero
d) None of these​

Answer 1

Answer:

Force experience by a charge at the center of ring is zero.

Explanation:

Given a ring of radius r carrying a charge Q

The electric field experienced at a distance by a ring is

                           $E=\frac{1}{4\pi \varepsilon_{0} } } \frac{Qx}{(x^{2}+r^{2} )^{3/2} }$

Force on charge q in the ring is given by

                      $F=qE=\frac{1}{4\pi \varepsilon_{0} } } \frac{qQx}{(x^{2}+r^{2} )^{3/2} }} }$    

As the charge q is at the center, $x=0$.

Therefore the force on charge is zero.