For a uniformly charged ring of radius R, the electric field on its axis has the largest magnitude at a distance h from its centre. Then value of h is:
a. 

b. 
R 
c. 

d. 
R 
For a uniformly charged ring of radius R, the electric field on its axis has the largest magnitude at a distance h from its centre. Then value of h is:
a. 

b. 
R 
c. 

d. 
R 
Electric field on axis of ring
E=
For maximum electric field
= 0
h =