Question

if a conducting sphere x comes in contact with another conducting sphere y initially in charge and has a radius twice that of x what is the force on sphere x after sphere y has been removed

Answer 1

Explanation:

When the two metal spheres are touched they will come to equal potential. And when the metal sphere are of same radius then the equal potential means equal charges.

Now the charge distribution at each steps will be-

Initially- A=+6q B=-3q C=0

Spheres A, B touched and seperated- A= +1.5q B=+1.5q C=0 ( charges will be equally distributed and total charge will be conserved for two spheres that are touched)

C and A are touched- A=+0.75q B=+1.5q C=+0.75q (same logic as above)

C and B are touched- A=+0.75q B=+1.125q C=1.125q

So the final charge on sphere C will be q

c

=+1.125q.