Chapter 21.2, Problem 47SSC

a.

To determine

The potential of the charged spheres when in contact.

Explanation of Solution

Introduction:

When a charged body touches another body, there is transfer of charges between them. The electric potential of the body decides the flow of the charges.

When the negatively charged sphere touches the positively charged sphere, the electrons from the negatively charged sphere moves to the positively charged sphere till both the bodies have the same potential. This is a state of equilibrium.

Conclusion:

Both the spheres have the same potential.

b.

To determine

The charges of the two spheres when placed in contact with each other.

Explanation of Solution

Introduction:

When a charged body touches another body there is transfer of charges between them. The electric potential of the body decides the flow of the charges. Electrons flow from a body of low potential to a body of higher potential.

When the spheres are in contact, electrons flow from the negatively charged sphere to the positively charged sphere. The final sign of the charge of the sphere depends on which sphere had more charge in the beginning. The final signs will be the same for both the spheres and the larger sphere will have more charge than the smaller sphere.

Conclusion:

The larger sphere will have more charge and both the spheres will have the same sign.