Answer:
 and
 and 
Explanation:
According to Coulomb's law, the magnitude of  force between two point object having change  and
 and  and by a dicstanced is
 and by a dicstanced is

Where,  is the permitivity of free space and
 is the permitivity of free space and 
 in SI unit.
 in SI unit.
Before  dcollision:
Charges on both the sphere are  and
 and  , d=20cm=0.2m, and
, d=20cm=0.2m, and  N
 N
So, from equation (i)


After dcollision: Each ephere have same charge, as at the time of collision there was contach and due to this charge get redistributed which made the charge density equal for both the sphere t. So, both have equal amount of charhe as both are identical.
Charges on both the sphere are mean of total charge, i.e 

 d=20cm=0.2m, and  N
 N
So, from equation (i)



As given that the force is repulsive, so both the sphere have the same nature of charge, either positive or negative, so, here take the magnitude of the charge.


The equation (ii) become:



From equation (iii)

So, the magnitude of initial charges on both the sphere are  Coulombs
 Coulombs and
 and  Colombs or
 Colombs or  .
.
Considerion the nature of charges too, 
 and
 and 