Question

Two identical conducting spheres carry charges Q and 2 Q. When separated by a distance much larger than their diameters, the spheres exert an electrostatic force F on each other. The two spheres are brought into electrical contact and then returned to their original separation. The final electrostatic force between the spheres is________________.

Answer 1

Step-by-step explanation:

Charges are Q and 2Q

distance = d

Force = F

Use coulomb's law

`F = (KQ * 2Q)/(d^(2))`

`F = (2KQ^(2))/(d^(2))` ... (1)

As they are in contact to each other the charges are shared.

Charge on each sphere, Q' = (Q + 2Q) /2 = 1.5 Q

Let the force is F'

By using Coulomb's law

`F' = (K* 1.5* 1.5Q^(2))/(d^(2))`

`F' = (2.25KQ^(2))/(d^(2))` ..... (2)

Divide equation (2) by equation (1)

`(F')/(F) = (2.25)/(2)`

F' = 1.125 F