Q1. Choose the correct option.                     

(a)Hot objects which can transfer heat by radiation are:

(i) only solids (ii) only gases (iii) both liquid and gases (iv)all liquids, gases, and solids.

Answer. (iv) all liquids, gases, and solids

(b) A steel spoon is dipped in a cup of ice cream. It’s the other end.

(i) Becomes cold by the process of conduction.

(ii) becomes cold by the process of convection.

(iii)becomes cold by the process of radiation.

(iv)does not become cold.

Answer. Becomes cold by the process of conduction.

(c) Which of the following is good conductor of heat?

(i) Plastic (ii) Wood (iii) Iron (iv) Rubber.

Answer. (iii) Iron

d. Land breeze is the:

(i) Flow of cool air from the land towards the sea.

(ii)Flow of cool air from the sea towards the land.

(iii) Flow of hot air from the land towards the sea.

(iv) Flow of hot air from the sea towards the land.

Answer. (i) Flow of cool air from the land towards the sea.

Q2. Match the columns.

Column A	Column B
(a)Sea breeze	(i) Winter
(b)Land breeze	(ii)Day time
(c) Dark coloured clothes	(iii) Summer
(d)Light coloured clothes	(iv) Night time.

Answer.

Column A	Column B
(a)Sea breeze	(i) Day time
(b)Land breeze	(ii)Night time
(c) Dark coloured clothes	(iii) winter
(d)Light coloured clothes	(iv) Summer

Q3. Fill in the blanks.

• ___________ is used as a thermometric liquid as it is a good conductor of heat.
• The ________ thermometer has a kink.
• While measuring temperature we should not hold a thermometer by its _______
• The heat from the sun reaches the earth through the process of ________

(a) Mercury is used as a thermometric liquid as it is a good conductor of heat.
(b) The clinical thermometer has a kink.
(c) While measuring temperature, we should not hold a thermometer by its bulb.
(d) The heat from the sun reaches the earth through the process of radiation.

Q4. Define the following.

• Heat.
• Insulator.
• Temperature.

(a) Heat: Heat is a form of energy that causes substances to become hotter or cooler, and it flows from hotter objects to colder ones until equilibrium is reached.

(b) Insulator: An insulator is a material that does not allow heat or electricity to pass through it easily, such as wood, plastic, or rubber.

(c) Temperature: Temperature is a measure of how hot or cold an object is, reflecting the average kinetic energy of particles within the object.

Q5. Answer the following questions in 2-3 sentences.

(a)State one similarity and one difference between the laboratory thermometer and the clinical thermometer.

Answer. Similarity: Both laboratory and clinical thermometers are used to measure temperature accurately.

Difference: A clinical thermometer has a kink to prevent mercury from falling back quickly, while a laboratory thermometer does not have this feature.

(b)In winters, why is wearing more layers of clothes better than wearing one thick jacket?

Answer. Wearing multiple layers traps warm air between each layer, which provides better insulation against the cold. This keeps the body warmer compared to a single thick jacket, which may not trap as much warm air.

(c)Hot objects lose heat faster than cold objects Why?

Answer. Hot objects lose heat faster because the temperature difference between the hot object and its surroundings is greater, causing heat to transfer more quickly to the cooler environment. This process continues until thermal equilibrium is reached.