Conductors and Insulators

Q.

Which metals is the best conductors of electricity?

1. Nickel

2. Silver

3. Gold

4. Sodium

Q.

What is meant by conductors and insulators ? Give two examples of conductors and two of insulators.

Q.

Define resistance.

Q.

Why is electric field zero inside a charged conductor?

Q.

The atoms of copper contain electrons and the atoms of rubber also contain electrons. Then why does copper conduct electricity but rubber does not conduct electricity?

Q. Question 18 (e)
Explain:
(e) Why are copper and aluminum wires usually employed for electricity transmission?

Q. What is benjamin franklin's experiment?

Q.

Why is there no charge inside a conductor?

Q.

Is Earth a conductor?

Q.

What is a charge? What is charging?

Q.

State three applications of heat conductors.

Q. Dry air is a good conductor of electricity.

1. False
2. True

Q.

The substance having infinitely high electrical resistance is called:
(a) conductor (b) resistor (c) superconductor (d) insulator

Q.

The substances which lose their resistance completely at very low temperature are called __

Q.

When conductors are placed in an electric field, their electrons are moved

1. Randomly in the direction of the electrical field

2. In the direction of the applied field

3. Randomly in all the directions

4. In the direction opposite the electrical field

Q.

Which of the following are conductors and which are insulators? Sulphur, Silver, Copper, Cotton, Aluminium, Air, Nichrome, Graphite, Paper, Porcelain, Mercury, Mica, Bakelite, Polythene, Maganin.

Q. Dry air is a good conductor of electricity. True or False?

1. True
2. False

Q.

Silk thread is a good conductor of electricity

1. True
2. False

Q. Mercury is a bad conductor of heat.

1. True
2. False

Q.

Which among Iron and Mercury is a better conductor of electricity?

Q.

Assertion: At high-temperature, metal wires have a greater chance of short-circuiting

Reason: Both resistance and resistivity vary with temperature.

Is reason correct explanation of the assertion?

1. Both A and R are true and R is the correct explanation

2. A is true but R is false

3. Both A and R are false

4. Both A and R are true but R is not the correct explanation

Q.

The electrical resistance of the insulator is?

Q. The SI Unit of resistivity is___

1. $\Omega m$
2. $\frac{\Omega }{V}$
3. $\frac{\Omega }{m}$
4. $\Omega A$

Q.

State the order of specific resistance of (i) a metal, (ii) a semiconductor, and (iii) an insulator.

Q.

Insulators can be charged but cannot conduct electric current.

1. True

2. False

Q.

A substance has nearly zero resistance at a temperature of 1 K. Such a substance is called:

1. Ideal Resistance

2. Semiconductor

3. Ideal Conductor

4. Superconductor

Q.

What is the general name of the substances having infinitely high electrical resistance?

Q.

Copper and Aluminium wires are used as connecting wires in an electrical circuit.

1. True
2. False

Q.

Why insulators are used as covering for electric wires?

Q.

Distinguish between good conductors, resistors and insulators. Name two good conductors, two resistors and two insulators.