Effects of Heat

Q.

Electrical wires stretch and sag during summer, because it expands on heating.

1. False
2. True

Q. Which use of the expansion of liquids in daily life do you know?

Q. Arrange the following in the decreasing order of kinetic energy of molecules.

1. Steam at ${101}^{\circ }C$
2. $\mathrm{Water}\mathrm{at}{80}^{\circ }C$
3. Water at ${50}^{\circ }C$
4. Ice at $-{10}^{\circ }C$

Q.

The iron rims are fitted to the wooden wheels of bullock carts and tongas by process of _____________.

Q.

Choose the correct options regarding the thermal expansion of liquids.

1. Liquid does not expands on heating

2. Real expansion is the sum of apparent expansion of Liquid and expansion of the vessel

3. Real expansion depends on expansion of the vessel

4. Real expansion is the difference of apparent expansion of liquid and expansion of the vessel

Q.

Change in length of a material depends on its ______.

1. ony final length is sufficient

2. initial and final length

3. initial temperature

4. intial and final length as well as temperature

Q.

The lengths of steel and copper rods are so that the length of the steel rod is $5cm$ longer than that of the copper rod at all temperatures. What will be the length of each rod?

Q.

Bridges are kept on rollers to allow for contraction in summer and expansion in winter.

1. True
2. False

Q. Which use of the expansion of liquids in daily life do you know?

Q.

Water is poured in a steel container for heating. The level of water in the container after heating will ___.

1. increase

2. decrease

3. increase/decrease

4. remains same

Q.

On heating ice changes to water vapour.

1. True
2. False

Q.

Why are the metal pipes arranged in the form of loops in many industries?

Q. Liquid is filled in a flask up to a certain point at room temperature. When the flask is heated, the level of the liquid

1. Rises abruptly
2. Immediately starts increasing
3. Initially falls and then rises
4. Falls abruptly

Q.

3. The iron blade of a spade is fixed to a wooden handle. Describe.

Q. 1) Why does bubbles appearwhen a liquid is heated??
2) What is the change in average kinetic energy of molecules of a liquid during boiling at its boiling point??
3) How is heat is supplied to a liquid used during boiling at a fixed temperature??
4) Name two ways of changing liquid state to the vapour state and distinguish them??

Q.

An increase in pressure increases the melting point. This statement is true for

1. ice and brass

2. silver and gold

3. brass and gold

4. Ice and silver

Q. $1\text{L}$ of water is taken into a vessel and is heated to ${80}^{\circ }\text{C}$. The contents of the vessel are transferred into a thermos flask of $1\text{L}$ capacity. It is observed that there is more water left in the vessel. Explain the reason for this.

Q.

Answer the following question in brief: What is the interconversion of matter.

Q.

Iron rims of slightly smaller diameter are mounted on the wooden wheels of the cart because:

1. iron does not allow the wooden wheel to wear off

2. iron expands on heating and slips over the wooden wheel

3. iron strengthens the wheel

4. none of the above

Q.

Name the following: Boiling point of water in Fahrenheit scale.

Q. Which of the following object(s) is/are hot at room temperature?

1. Ice cream
2. Snow
3. Molten wax
4. Boiling water
5. Burning coal

6. Hot iron

7. Chilled coffee
8. Steam

Q. Which of the following will radiate heat to a large extent?

1. Rough surface
2. Polished surface
3. Black rough surface
4. Black polished surface

Q. Expansion during heating :

1. occurs only in solids
2. decreases the density of the material
3. occurs at the same rate for all liquids and gases
4. increases the weight of the material

Q. If we put a cello tape on balloon and then insert a stick in balloon, itll not burst. Why this happens??

Q. Name two ways of change of liquid state to the vapour state and distinguish them