Conductors and Insulators

Q. Two copper wire A and B of length 30m and 10m have radii 2cm and 1cm respectively. Compare the resistance of the two wires. Which will have less resistance?

Q.

Mercury is a metal, is it a good conductor of electricity? If not why

Q.

Why are metals good conductors of electricity whereas glass is a bad conductor of electricity? Give reason.

Q.

Rubber is a good conductor of electricity.

1. Insulator

2. Conductor

Q.

Which of the following material is a good conductor of electricity?

1. Rubber

2. Silver

3. Plastic

4. Wood

Q.

An electrician uses rubber or plastic gloves while repairing an electric switch at home because:

1. It is a insulator

2. it is a conductor

3. he likes using rubber plastic gloves

4. None of these

Q.

Why are the electric wires used in homes usually covered with materials like plastic or rubber?

1. To prevent rusting.

2. To make handling easier.

3. To prevent shock.

4. To make them look beautiful.

Q.

What type of material allows electrons to flow freely?

1. Conductor

2. Resistor

3. Hestitation

4. Regulator

Q.

An electrician uses rubber or plastic gloves while repairing an electric appliance because ______.

1. it acts as an insulator

2. it acts as a conductor

3. it enhances convenience in handling wires

4. it protects from the radiations

Q. A wire of a certain material is stretched slowly by 10%.Its new resistance and specific resistance becomes

Q.

The human body is an electric insulator.

1. True

2. False

Q.

What is a good conductor? Give two examples.

Q.

Plastic is good conductor of electricity

1. True
2. False

Q. a wire of resistance R and of radius r is drawn into another wire of radius 2r, the new resistance of the wire will be-

Q.

Classify the following into good conductors, resistors, and insulators: rubber, mercury, nichrome, polythene, aluminum, wood, manganin, bakelite, iron, paper, thermocol, metal coin

Q.

Silver is an insulator of electricity.

1. True
2. False

Q.

When an object has very high resistance, it can be called a good conductor.

1. True

2. False

Q.

The objects which allow an electric current to flow through them easily are known as

Q.

A long wire will have:

1. More tensile strength

2. Same resistance as short wire

3. Less resistance than short wire

4. More resistance than short wire

Q.

Which of the following is a good insulator and conductor pair?

1. Wood and plastic

2. Plastic and rubber

3. Plastic and Copper

4. Wood and rubber

Q.

Which of the following material is not a good conductor of electricity?

1. A plastic tube

2. Wet slippers

3. Silver

4. Copper

Q. Heat transfer from one end to the other in an iron rod occurs through _____.

1. radiation
2. conduction
3. vaporization
4. convection

Q.

Switches, electrical plugs and sockets are normally made up of which among the following metal(s)?

1. Brass

2. Copper

3. Gold

4. Silver

Q. Which of the following materials is a good conductor of electricity?

1. Rubber
2. Wood
3. Silver
4. Plastic

Q.

Which of the following is true about current carrying conductors?

1. They behave as magnets when current does not flow through them.

2. They behave as magnets when current flows through them.

3. They can never behave as a magnet.

4. They are permanent magnets.

Q. Why does a electric bulb glow in yellow and CFLs in white colours?

Q.

Which of the following pairs consist of a conductor and an insulator of electricity?

1. Copper and steel

2. Paper and gold

3. Silver and rubber

4. Wood and wool

Q. Instead of a copper wire, a string can be used for making connections in electrical circuits.

1. silver
2. plastic
3. jute
4. clay

Q.

The glass is an example of:

1. conductor

2. insulator

3. electric cell

4. All of these

Q.

Electric current can pass through a sheet of thermocol.

1. True
2. False