Linear Expansion

Q. On heating a bimetallic strip (made of brass & iron), the brass strip expands more. This is because the linear coefficient of expansion for iron is.

1. greater than brass
2. less than brass
3. equal to brass

Q. An object is projected so that it just clears two walls of height 7.5 m and with separation 50 m from each other. If the time passing between the walls is 2.5 s, the range of the projectile will be ..... (g = 10 m/s^2
a) 35 m
B) 70 m
C) 140 m
D) 57.5 m

Q.

What do you understand by the following terms :Cubical expansion

Q.

Two rods of length ${\mathrm{l}}_1$ and ${\mathrm{l}}_2$ are made of materials whose coefficients of linear expansion are ${\mathrm{\alpha }}_1$ and ${\mathrm{\alpha }}_2$. If at a certain change in temperature, the change in length of the rods are the same, what is the ratio of the original lengths of the rods?

1. ${\mathrm{\alpha }}_1:{\mathrm{\alpha }}_2$

2. ${\mathrm{\alpha }}_2:{\mathrm{\alpha }}_1$

3. 1:1

4. Cannot be determined

Q.

Two identical copper rods, one hollow and the other solid are heated to the same rise in temperature. Will the two rods expand equally or unequally?

Q.

Two identical rods - one hollow and the other solid, are heated to the same rise in temperature. Which will expand more?

Q.

Two iron rods - one 10 m long and the other 5 m long, are heated to the same rise in temperature. Which will expand more?

Q. How can be prove that molar value = 22.4 liter at NTP ?

Q. The increase in the length of an iron rod on heating is called

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

Q.

State three factors on which depend the linear expansion of a metal rod on heating.

Q.

One rod of copper and another identical rod of iron are heated to the same rise in temperature. Which rod will expand more? Give reason.

Q.

Two identical rods of copper is heated to different temperatures - one by $5^{\circ }C$ and the other by ${10}^{\circ }C$. Which rod will expand more?

Q.

Equal lengths of different solids expand by equal amounts when heated equally.

1. True
2. False

Q.

What is the unit of linear expansion coefficient of a solid? Which expands more, iron or brass?

Q.

Sagging of telephone wires during summer is due to thermal expansion.

1. True
2. False

Q.

A metallic washer of internal diameter $5cm$ is heated by $500{}^{\circ }C$. If the coefficient of linear expansion of metal is $1.8\times {10}^{-5}$ per ${}^{\circ }C$, then the final diameter will be 5.045

1. False

2. True

Q.

While making tea or something on a gas stove in a metal beaker . Why don't the metal beaker don't expand because of heat?

Q. If a bimetallic strip is heated it will

1. Have no bending
2. Bend towards the metal with higher thermal expansion coefficient
3. Bend towards the metal with lower thermal expansion coefficient
4. Twist itself into a helix

Q. Increase in length per unit of the length, per degree celsius rise in temperature is called coefficient of linear expansion. Type 1 for true and 0 for false

Q. You measure the length of a brass rod on a hot July afternoon and a cool January evening, using the same aluminium scale. To your surprise, you find that the rod length is measured to be smaller on the summer day! How?

1. None of these
2. Aluminium expands more on heating than brass
3. Aluminium expands lesser than brass on heating
4. Brass shrinks on heating

Q. A circular metal disc of diameter $5cm$ is heated by $500{}^{\circ }C$. If the coefficient of linear expansion of metal is $1.8\times {10}^{-5}{}^{\circ }{C}^{-1}$, what will be its final diameter?

1. 4.945 cm

2. 5.045 cm

3. 5.450 cm

4. 5.001 cm

Q.

An iron ring is heated uniformly. Which of the following will be affected?

1. Internal diameter

2. External diameter

3. Mass

4. None of these

Q. The maximum possible reduction in length in the given 1 m steel rod is

1. 39.0 mm
2. 3.9 mm
3. 0.70 mm
4. 1.95 mm

Q. The increase in the length of an iron rod on heating is called linear thermal expansion.

1. True
2. False

Q.

Small gaps are left between railway lines because

1. We cannot have rails of very long length.

2. It allows for expansion of rails during summer.

3. It allows for contraction of rails during summer.

4. Both (ii) and (iii).

Q. Why do electric cables sag in summer?

1. Due to thermal expansion
2. Due to low pressure
3. Due to moisture
4. Due to dry climate

Q. Match the materials with their respective coefficients of linear expansion (in the order of ${10}^{-6}{}^{\circ }{\text{C}}^{-1}$)

1. Steel
2. Aluminium
3. 16.5
4. 1.5
5. Copper
6. 12
7. 22
8. Invar

Q. Match the following types of expansion with the formula to calculate the respective increment.

1. Linear
2. ${\text{l}}_{\text{t}}-{\text{l}}_{\text{0}}={\text{l}}_{\text{0}}\alpha \text{t}$
3. Superficial
4. ${\text{A}}_{\text{t}}-{\text{A}}_{\text{0}}={\text{A}}_{\text{0}}\beta \text{t}$
5. Cubical
6. ${\text{V}}_{\text{t}}-{\text{V}}_{\text{0}}={\text{V}}_{\text{0}}\gamma \text{t}$