a charged particle having some mass is resting in equilibrium at height h above the centre of a uniformly charged non conduction horizontal ring of radius R, The force of gravity acts downwards , the equilibrium of the particle will be stable :

1. for all values of h
2. only if h>R/root2
3. only if h
4. only if h=R/root2

Dear student,

Please find the answer to your question below.

 

The conditions for stable equilibrium can only be true if H > R/√2 , because in this region the electric field increase if H decreases and decreases if H increases. Due to which a slight displacement in vertical direction either upwards or downwards brings back the charge particle back to the same place eventually or the net resultant force acts always towards the direction of equilibrium position.

 

Thanks and regards,

Kushagra