Heat and Electricity

Q.

Difference between short-circuit and overloading

Q. Which of the following does not work on the principle of heating effect of electric current?

1. Electric kettle
2. Water pump
3. Rice cooker
4. Microwave oven

Q. Which of the following devices consumes least electrical energy for the same light intensity?

1. Incandescent electric bulbs
2. Fluorescent tube-lights
3. Compact fluorescent lamps (CFLs)
4. Light emitting diode (LED) bulbs

Q. An electric bulb works on the principle of effect of electric current.

1. magnetic
2. heating
3. chemical

Q.

When a current flows through a conductor, its temperature

1. Increases

2. Decreases

3. Remains same

4. May increase or decrease

Q. Electric cooker contains a coil made up of _______ that gets heated up when electricity passes through it.

1. Nichrome
2. Copper
3. Zinc
4. Alnico

Q. Which of the following is the most energy efficient light fixture?

Q.

State the characteristics required in a material to be used as on effective fuse wire.

Q.

Bulb glows only in

1. closed circuit

2. open circuit

3. in both circuits

4. open circuit if bulb is not fused

Q.

State any three applications of electromagnet.

Q. Which of the following usually requires least power to operate?

1. CFLs

2. 100 W bulbs

3. Tubelights

4. Electric Oven

Q. Wastage of electricity can be reduced by using _____.

1. tube lights
2. MCBs
3. CFLs
4. electric fuses

Q.

Meter Bridge or Slide Wire Bridge is a practical form of which?

Q.

Suggest three ways to produce a temporary magnetic field. Explain any one of them in detail.

Q. In the circuit given below, what will happen if you disconnect the wire from one of the battery terminals?

1. The brightness of the bulb would decrease.
2. Bulb would not glow.
3. Bulb would fuse.
4. The brightness of the bulb would increase.

Q. Explain the two effects of electric current along with their principles and uses. [3 MARKS]

Q.

An electromagnet works on the magnetic effect of _____________

Q. Which of the following does NOT contain a heating element?

1. Compact Fluorescent Lamp
2. Electric iron
3. Electric heater
4. Electric oven

Q.

Name the material used for:

Electric fuse

Q. Which of the following household appliances does not use a magnetic field?
1) electric fan
2) electric iron
3) TV
4) mixer grinder
with explanation

Q.

Why is negligible heat produced in connected wires of Cu?

Q. Three wires A, B, and C are made up of same material and have the same length. ​The order of their cross-sectional areas is C > B > A. If the same amount of current flows through all the three wires, the order of heat generation will be:

1. C > A > B​
2. A > B > C​​
3. C > B > A​
4. A > C > B​​

Q.

State whether the following statement is true or false.

LED lights and CFLs convert mechanical energy into light energy.

1. True
2. False

Q. Choose the correct option with reference to the heat generated in the given diagram:

1. A > B
2. A < B
3. A = B
4. Can't say

Q. The amount of heat developed in an electric wire depends upon its:

1. Material
2. Color
3. Thickness
4. Length

Q. What are the factors upon which the amount of heat produced in a wire depend?
(i) Material
(ii) Length
(iii) Thickness

1. Only (i) and (ii)
2. Only (i) and (iii)
3. (i), (ii) and (iii)
4. Only (ii) and (iii)

Q. Bulbs with filament works on the principle of heating effect of electric current.

1. False
2. True

Q.

Electromagnet is a _________ magnet.

Q.

In the case of an electric cell, the armature is connected to a hammer made of plastic.

1. True
2. False

Q.

WHAT IS THE DIFFERENCE BETWEEN A MCB(MINIATURE CIRCUT BREAKER AND A FUSE WIRE?