A point charge q is placed inside a neutral conducting spherical shell of inner radius 2r and outer radius 3r at a distance of r from the centre of the shell. The electric potential at the centre of shell will be times
Answers
1. Two identical conducting spheres A and B carry equal charge Q. They are separated by a
distance much larger than their diameters. A third identical conducting sphere C carries charge
2Q. Sphere C is first touched to A, then to B, and finally removed. As a result, the electrostatic
force between A and B, which was originally F, becomes:
Solution:
After C touches A, = ; + = 3 ⇒ = =
.
Then C touches B, = ′; + ′ =
⇒ = ′ =
.
Coulomb’s law gives
=
=
=
.
2. In the figure shown, what is the magnitude of the net electric force (in N) exerted on charge q2
by charges q1 and q3, given that d1 = 3 nm and d2 = 6 nm?
Solution:
The x and y components of Coulomb force on q2 are
=
24
= 1.54 × 10%&'; ( =
2
= 0.51 × 10%&'
The net force is = )
+ (
= 1.6 × 10%&'