Solution:
i) Given:
Charge on sphere
Charge on sphere
Distance between the spheres,
Concept: We know that Force of repulsion between the two spheres,
Where Permittivity of free space and
Calculation: Substituting the value of parameter and evaluating the value:
Final Answer: Therefore, the force between the two spheres is
(ii) Given: After doubling the charge,
Charge on sphere A,
Charge on sphere B,
The distance between the spheres is halved.
Calculation: Force of repulsion between the two spheres,
N
N
Final Answer: Therefore, the force between the two spheres is