Thermal Expansion of Solids

Q. The coefficient of thermal expansion of an aluminium rod is ​23 × ${10}^{-6}$$°C^{-1}$. If so, the coefficient of thermal expansion ​of a spherical aluminium ball will be: ​

1. 69 × ${10}^{-6}$$°C^{-1}$
2. 23 × ${10}^{-6}$$°C^{-1}$
3. 7.6 × ${10}^{-5}$$°C^{-1}$
4. 46 × ${10}^{-6}$$°C^{-1}$

Q. Two rods A and B of the same metal, but of length $1\text{m}$ and $2\text{m}$ respectively, are heated from $0{}^{\circ }\text{C}$ to $100{}^{\circ }\text{C}$. Then, ___.

1. both A and B elongate the same.
2. A elongates, but B contracts.
3. B elongates more than A.
4. A elongates more than B.

Q. A solid ball of metal has a concentric spherical cavity within it.
What change can you observe in the volume of the cavity when the ball is heated?

1. Volume of the cavity increases
2. Volume of the cavity remains same
3. Volume of the cavity decreases
4. Volume of the cavity reduces to half of it's initial volume

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. Lower thermal expansion of solids is related to

1. low melting point
2. high melting point
3. chemical change
4. low boiling point

Q.

Brass and iron will have same rate of linear expansion.

1. True

2. False

Q.

A cubical metal solid block is heated. It will experience only a superficial expansion.

1. True

2. False

Q. What should be the temperature rise of a brass rod , so as to increase its length by $1\%$? (Given: coefficient of linear expansion of glass rod, $\alpha =2\times {10}^{-5}{}^{\circ }{C}^{-1})$.

1. 200 ⁰C

2. 100 ⁰C

3. 1000 ⁰C

4. 500 ⁰C

Q. Pick the incorrect statement regarding a thermal insulator.

1. Keeps cold things cold
2. Makes hot things cold
3. Keeps warm things warm
4. Keeps hot things hot

Q. Normally, engineers keep a small gap at the joint between two rail tracks, because:

1. To reduce the train speed
2. To reduce noise
3. To change tracks
4. To counter thermal expansion