Sir please send me the solution of above mentioned problem regarding electrostatics

Final Answer :(-2£ ) where £ is surface charge density of h^mispherical shell. 

Steps and Understanding :

1)
We will first find electrostatic force on right half due to first half on horizontal direction. 
This will be done by integrating electrostatic pressure to all right half area 

2) Then, we will calculate the force in horizontal direction by small sphere as vertical component will get cancelled out. 

3) Then, we will add these two forces as 0 since right half is in equilibrium. 

After calculation, minimum surface charge density of small sphere is -2£.
But, magnitude of surface charge density can be even greater than this. 
But, Magnitude of Minimum is 2£.
This will be opposite in sign with given hemi
sphere.