Conductors and Insulators

Q.

Materials which do not allow electric current to flow through them is known as

Q.

Substances which have free electrons and offers high resistance are called as insulators.

1. True

2. False

Q.

State two differences between a conductor and an insulator of electricity.

Q.

A good conductor of heat is a bad conductor of electricity.

1. True
2. False

Q.

What are conductors and insulators of electricity ? Give two examples of each.

Q.

Why are copper and aluminium wires usually employed for electricity transmission? [1 MARK]

Q.

Is salt a conductor?

Q.

The insulator of electricity is :

(a) copper (b) acidulated water

(c) human body (d) silk

Q. Which of the following is a poor conductor of electricity?

1. Wool
2. Silver
3. Copper
4. Iron

Q. Resistance of good electrical conductors is zero.

1. True
2. False

Q. Insulators can be charged but do not conduct electric charge. State whether it is True or False.

1. True
2. False

Q.

Substance through which electricity can flow is _______.

Q.

Select conductors of electricity from the following: Copper wire, silk thread, pure water, acidulated water, a human body, glass, mercury.

Q.

When a potential difference is applied across the resistor, the path of an electron in the resistor is ___ .

1. Parabolic

2. Circular

3. Straight line

4. Zig zag

Q.

Identify the energy conversions in a closed, working circuit that enables continuous flow of current in it.

1. Electrical to chemical energy

2. Electrical to mechanical energy

3. Mechanical to electrical energy

4. Chemical to electrical energy.

Q.

During lightning, which of the following occurs?

1. There will be a flow of large number of electrons from the cloud to the ground.

2. There will be a flow of protons from the cloud to the ground.

3. No flow happens.

4. Depends upon the charge of cloud.

Q.

In dry cells, the _______ energy gets converted to the _________ energy.

Q. Which material is not suitable to make gloves for electrical activities?

1. Plastic
2. Leather
3. Rubber
4. Copper

Q.

Which of the following are examples of insulator?

1. Rubber

2. Leather

3. Copper

4. Glass

Q. Match the resistances that an ideal conductor offers at different temperatures.

1. zero resistance
2. low resistance
3. high resistance

Q.

What is the differencre between voltage and current (dc)

Q. What is the electric component that breaks an electric circuit in case of excess current?

1. Switch
2. Rheostat
3. Fuse wire
4. Galvanometer

Q. Which of the following wire can be used in electrical transmission lines

1. Tungsten
2. Copper
3. Manganin
4. Rubber

Q.

The substances having infinitely high electrical resistance are called ___________

Q. Electrons move at speed of about 1 mm/s. Then how does the light turn on as soon as we switch it on?

Q. Which of the following wires can be used between AC to complete the electrical circuit?

1. Plastic wire
2. Copper wire
3. Silver wire
4. Rubber wire

Q.

Which of the following is a non-metal that conducts electricity?

1. Silicon

2. Germanium

3. Graphite

4. Copper

Q. Identify the energy conversions in a closed, working circuit that enables continuous flow of current in it.

1. Electrical to mechanical energy
2. Electrical to chemical energy
3. Mechanical to electrical energy
4. Chemical to electrical energy.

Q.

how does current flows in an electrolyte

Q.

The wider the cross section of a conductor, the higher the current.

1. True

2. False