UPSEE Solved Model Paper 5

Let sphere 1 has the charge + 10C and sphere 2 has the charge - 20 C
When , they are separated at a distance R from each other , they experience force = k(10)

(−20)

R2

when they made contact
charge will start flowing from S1 to S2 till they both acquire same charge because of greater amt of charge in S1.
Now, resulting charge (average) in both the bodies is :
q1 = 10 + (- 20) / 2 = 5
so force F2 = k (-5) (-5) / R2
So F1/F2 after calculation comes
- 8 : 1