Conductor

Q. Upon charging by conduction, the mass of a body may :

1. Increase
2. Decrease
3. Increase or decrease
4. Remain the same

Q.

Why is it dangerous to touch a working electrical appliance with wet hands ?

Q. Why sand is used instead of water to put out electric fire?

1. Water does not have charge carriers.
2. Water can cause explosion.
   
3. Sand has charge carriers.
4. Sand does not have charge carriers.

Q.

How would you classify lemon juice - as good conductor or as a poor conductor of electricity ?

Q.

1. True
2. False

Q. If the radius of cross-section of the conductor is increased by 0.1% keeping volume constant then percentage change in the resistance of the conductor is-

Q.

When electric current flows through a metal, it is actually a flow of

___

Q. What causes the deflection of magnetic needle when the electricity is passed through the wire near it or wounded on it ?

Q.

All metals have free electrons that conduct electricity.

1. True
2. False

Q. Question 11
Name the effect of current responsible for the glow of the bulb in an electric circuit.

Q. Why it is preferable to classify materials into good or poor conductors instead of classifying into conductors or insulators?

Q. Why is it not safe for an electrician to carry out electrical repairs in the outdoor areas during heavy downpour?

Q.

The amount of heat produced in a conductor does not depend on

1. length

2. material

3. force

4. thickness

Q. The objects which allow electric current to flow through them easily are known as:

1. Radiators
2. Good conductors
3. Resistors
4. Insulators

Q. What constitutes an electric current in a metal?

Q.

Current is due to which of the following reason?

1. All of the above

2. Temperature of the conductor

3. Resistance of the conductor

4. Charge flowing through the conductor

Q. Evolution of gas on passing electric current through a conducting solution is an example of effect of electric current.

1. heating
2. magnetic
3. chemical

Q. What should be the characteristic of a fuse wire?

1. High melting point, high specific resistance
2. Low melting point, low specific resistance
3. High melting point, low specific resistance
4. Low melting point, high specific resistance

Q.

Break a wooden splint into half . Break these pieces further into smaller pieces .

Are the smallest pieces that you have obtained still wood?

Q. Poor conductors of electricity can allow electricity to pass through them under certain conditions.

1. True

2. False

Q.

The filament of a bulb glows due to?

1. Heating effect of the electric current.

2. Magnetic effect of electric current.

3. Chemical effect of electric current.

4. All of these.

Q. Why are iron food cans electroplated ​with tin for storing food? ​

Q.

Select the correct alternative:

(a) All wires used in electric circuits should be covered with:

(i) colouring material

(ii) conducting material

(iii) an insulting material

(iv) none of the above.

(b) Electrical work done per unit time is:

(i) electrical energy

(ii) electric current

(iii) electric voltage

(iv) electric power

(c) One kilowatt is equal to :

(i) 100 watt (ii) 1000 watt

(iii) 10 watt (iv) none of the these.

(d) Fuse wire is an alloy of :

(i) tin-lead (ii) copper-lead

(iii) tin-copper (iv) lead-silver

(e) A fuse wire should have :

(i) a low melting point

(ii) high melting point

(iii) very high melting point

(iv) none of the above.

(f) When the switch of an electric appliance is put off, it disconnects:

(i) the live wire

(ii) the neutral wire

(iii) the earth wire

(iv) the live and the neutral wires.

(g) The purpose of an electric meter in a house is :

(i) to give the cost of electricity directly

(ii) to give the consumption of electrical energy

(iii) to safeguard the circuit from short circuiting

(iv) to put on or off the mains.

(h) If out of the two lighted bulbs in a room, one bulb suddenly fuses, then:

(i) other bulb will glow more

(ii) other bulb will glow less

(iii) other bulb will also fuse

(iv) other bulb will remain lighted unaffected.

Q. The effect of current causes deflection in a compass needle when it is placed near a current-carrying wire.

1. heating
2. magnetic
3. chemical

Q. When a 40v/m electric field is produced inside a conductor then 210000A/m-2 current density is established in it.Resistivity of the conductor is.

Q. Which of the following cannot be used as an electrolyte?

1. Acetic acid solution
2. Distilled water
3. Copper sulphate solution
4. Salt water

Q.

Differentiate good and bad conductors

Q. Magnetic Needle shows deflection.What causes this deflection??

Q. Which of the folowing is not an application of electroplating?

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true, but R is not the correct explanation of A.
3. A is false, but R is true
4. A is true, but R is false

Q.

Which of the following objects can produce an electric current through a circuit?

1. Electric motor

2. Battery

3. Electric Bulb

4. Electric fan