A spherical conducting shell of inner radius $r_1$ and outer radius $r_2$ has a charge Q. A charge q is placed at the center of the shell. The surface charge density on the outer surfaces of the shell is:

1.	\(\frac{Q+q}{4 \pi r_{2}^{2}}\)	2.	\(\frac{q}{4 \pi r_{1}^{2}}\)
3.	\(\frac{-Q+q}{4 \pi r_{2}^{2}}\)	4.	\(\frac{-q}{4 \pi r_{1}^{2}}\)

 

A long charged cylinder of linear charged density is surrounded by a hollow co-axial conducting cylinder. What is the electric field in the space between the two cylinders at distance d from the common axis?
1. \(\frac{2 \lambda}{\pi \varepsilon_0 d}\)
2. \(\frac{\lambda}{2 \pi \varepsilon_0 d}\)
3. \(\frac{\lambda}{\pi \varepsilon_0 d}\)
4. \(\frac{\pi \lambda}{2 \varepsilon_0 d}\)

Sure check for the presence of electric charge is:

1. Process of induction

2. Repulsion between bodies

3. Attraction between bodies

4. Frictional force between bodies

If a solid and a hollow conducting sphere have the same radii then:

1. the hollow sphere will hold more maximum charge.

2. the solid sphere will hold more maximum charge.

3. both the spheres will hold the same maximum charge.

4. both the spheres can't hold a charge.

Five balls marked a to e are suspended using separate threads. Pairs (b, c) and (d, e) show electrostatic repulsion while pairs (a, b), (c, e) and (a, e) show electrostatic attraction. The ball marked a must be:

1. negatively charged.

2. positively charged.

3. uncharged.

4. Any of the above is possible

When a plastic rod rubbed with wool is brought near the knob of a negatively charged gold-leaf electroscope, the gold leaves:

1. Contract

2. Dilate

3. Start oscillating

4. Collapse completely

Which of the following is not true about the electric charge?

1. Charge on a body is always an integral multiple of a certain charge known as the charge of an electron.

2. Charge is a scalar quantity.

3. Net charge on an isolated system is always conserved.

4. Charge can be converted into energy and energy can be converted into charge.

Which of the following processes involves the principle of electrostatic induction?

1. Pollination

2. Chocolate making

3. Xerox copying

4. All of these

When a conducting soap bubble is negatively charged then:

1. Its size starts varying arbitrarily

2. It expands

3. It contracts

4. No change in its size takes place

Coulomb's law is analogous to:

1. Charge conservation law

2. Newton's second law of motion

3. Law of conservation of energy

4. Newton's law of gravitation