Thermal Expansion

Q. Write down any two examples of thermal expansion in daily life.

Q. Why does the mercury in a clinical thermometer not fall or rise when removed from the mouth?

1. Because of the kink present in the thermometer
2. None of the above
3. Because mercury is transparent, therefore, we cannot observe its fall or rise
4. Because mercury sticks to the wall of the thermometer.

Q.

"A substance expands on heating and contracts on cooling”. Justify this statement. [2 MARKS]

Q. State which expands more, when heated to the same temperature : solid, liquid or gas ?

Q. For a melting of NaCl heat required is 7.26kcal mol and Entropy change increased by 6.73 cal mol .the melting of the salt is

Q.

The increase in area of a particular solid on heating is called

1. all of these.

2. linear expansion

3. superficial expansion

4. cubical expansion

Q. The expansion in length of an object due to heat, is called

1. linear expansion
2. superficial expansion
3. cubical expansion
4. chemical expansion

Q.

A Kink is present in a laboratory thermometer.

Say True or False.

1. True

2. False

Q.

Can you suggest one more example in your daily life that uses the principle of expansion of solids?

Q.

From the top of a tower of height 490 m, a shell is fired horizontally with a velocity 100 m/s. At what distance from the bottom of the tower, the shell will hit the ground? (Give the answer in m)

1. 100
2. 0
3. 10

4. 1000

Q. What do you understand by thermal expansion of a substance ?

Q.

Write the applications of thermal expansion of solids.

Q.

What is thermal expansion? Given an example of thermal expansion of solids?

Q. On heating a rod, its length increases. On what factors does the increase in length depend on?

1. The material of the rod
2. The length of the original rod
3. The increase in its temperature
4. None of the above.

Q.

Give reason for the statement

A normal glass tumbler cracks when dipped in boiling water. Why?

Q. ___ in a clinical thermometer is responsible for keeping the level of mercury from falling even after we take it out of our mouth.

1. Bimetallic strip
2. Bulb
3. Capillary
4. Constriction

Q.

A vessel with a negligible heat capacity contains $1000g$ ice at $0°\mathrm{C}$. Into it is poured $100g$ of water at $100°\mathrm{C}$. What would be the result at the end of experiment ?
[Take SHC of water $=4.2{\mathrm{Jg}}^{-1}{{}^{\circ }\mathrm{C}}^{-1}$and SLH of ice $=336{\mathrm{Jg}}^{-1}$ ]

Q. You measure the length of a brass rod on a hot summer day and a cold winter night using the same aluminium scale. To your surprise, you find that the length of a brass rod is found to be smaller on a hot summer day than on the winter night. Assuming that the brass rod and the aluminium scale have the same length during winter, which of the following could explain the above phenomena?

1. 
   Aluminium expands more than brass on heating
2. 
   Aluminium contracts on heating
3. 
   Brass shrinks on heating
4. 
   Aluminium expands less than brass on heating

Q. State the precautions while using clinical thermometer.

Q.

The increase in the volume of a substance (solid, liquid, or gas) when heated, is called cubical expansion.

1. True
2. False

Q.

Thermal expansion is the highest in solids.

1. True
2. False

Q.

Why does a Pyrex glass not crack when hot water is poured into it? Explain.

Q. The expansion in area is called__________.

1. linear expansion
2. superficial expansion
3. cubical expansion
4. chemical expansion

Q.

When a substance takes the heat without the change of state, then its ___ expands.

Q.

Thermal expansion only has bad effects.

1. True
2. False

Q.

A marble tile would feel cold as compared to a wooden tile on a winter morning because the marble tile

1. is a better conductor of heat than the wooden tile.

2. is polished while the wooden tile is not polished.

3. reflects more heat than wooden tile.

4. is a poor conductor of heat than the wooden tile.

Q. The heat generated by radioactivity within the earth is conducted outward through the oceans. Assuming the average temperature gradient within the solid earth beneath the ocean to be ${0.07}^{\circ }{C}^{-1}$ and the average thermal conductivity $0.2cal{m}^{-1}{s}^{-1}{C}^{-1}$, determine the rate of heat transfer per square meter. Radius of the earth = 6400 km. Further, determine the quantity of heat transferred through the earth's surface each day.

1. 
2. 
3. 
4. 

Q.

Which effect of heat does the ball and ring experiment show? Explain this experiment.

Q.

Superficial and volume thermal expansions occur in solids, liquids and gases.

1. True
2. False

Q.

Thermal expansion is the property due to which increasing the temperature of an object changes its ___ .

1. weight

2. speed

3. dimensions or volume

4. colour