Question

Multiple Choice Questions :-

1. Solar cooker works on

(a) Conduction
(b) Convection
(c) Radiation

2. Substances which conduct heat easily are called

(a) Insulator
(b) Conductor
(c) Superconductor

3. Molecules do not move from the hotter body to the colder body in

(a) Radiation
(b) Conduction
(c) Convection

4. Which colour is the best radiator of heat?

(a) Red
(b) Black
(c) Green

5. Best wool is obtained from :-

(a) Camel
(b) Sheep
(c) Goat

6. Igloos are made of snow because snow

(a) is a good conductor of heat energy
(b) is a good absorber of heat energy
(c) does not melt at all
(d) is a good insulator of heat energy

7. A thermos flask is silvered to minimize

(a) Heat transfer by radiation
(b) Heat transfer by conduction
(c) Heat transfer by convection
(d) All of these

8. Which energy is always transferred from a hot body to a cold body?

(a) Heat energy
(b) Chemical energy
(c) Wind energy

9. Heat ___________ the vibration of the molecules

(a) Decrease
(b) Increase
(c) Both (a) and (b)

10. Which colour radiates more heat?

(a) Black
(b) White
(c) Green​

Answer 1

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1. (c.) Radiation
2. (b.) Conducters
3. (b.) Conduction
4. (b.) Black
5. (b.) Sheep
6. (d) is a good insulator of heat energy
7. (d.) All of these
8. (a.) Heat energy
9. (b.) increases
10. (b.) White

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Answer 2

1)Conduction.

Explanation:- Conduction is the transfer of heat from one object directly to another .The conducted heat is circulated in a cooker which cooks food.

2)Conductors.

Explanation:- Conductors are substances which allow heat to pass through them.

3)Conduction.

Explanation:-In conductor heat gets transferred where the molecules need not to move.

4)Black

Explanation:-Black is the darkest color darker the color the greater the radiation of heat.

5)Sheep

Explanation:-There is a type of sheep called Merino Sheep this sheep gives the highest quality of wool.

6)It is a good insulator of heat energy.

Explanation:-Igloos are made from compressed snow it is warm in the igloo as snow is an insulator and the dome shape gives protection from wind.

7)All of these.

Explanation:-There is vacuum in a flask which has vacuum inside silver reflects the radiation thereby reducing even conduction and convection.

8)Heat energy

Explanation:-Heat energy travels from the hot region to cold region due to conduction which is not possible in both Chemical and wind energy.

9)Increase

Explanation:-When the temperature is high the molecules perform more vibration and when colder the vibration reduces.

Fact:-Molecules stop vibrating at Absolute zero which is the coldest temperature possible which is -273.15°C.

10)Black

Explanation:-Darker the color more the radiation of heat and black is the darkest color.