# NCERT Class 11 Physics Chapter 11 Thermal Properties of Matter CBSE Board Sample Problems

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## MCQ II

Question 9:

Mark the correct options:

(a) A system X is in thermal equilibrium with Y but not with Z. System Y and Z may be in thermal equilibrium with each other.

(b) A system X is in thermal equilibrium with Y but not with Z. Systems Y and Z are not in thermal equilibrium with each other.

(c) A system X is neither in thermal equilibrium with Y nor with

Z. The systems Y and Z must be in thermal equilibrium with each other.

(d) A system X is neither in thermal equilibrium with Y nor with Z. The system Y and Z may be in thermal equilibrium with each other.

Question 10:

‘Gulab Jamuns’ (assumed to be spherical) are to be heated in an oven. They are available in two sizes, one twice bigger (in radius) than the other. Pizzas (assumed to be discs) are also to be heated in oven. They are also in two sizes, one twice big (in radius) than the other. All four are put together to be heated to oven temperature. Choose the correct option from the following:

(a) Both size gulab jamuns will get heated in the same time.

(b) Smaller gulab jamuns are heated before bigger ones.

(c) Smaller pizzas are heated before bigger ones.

(d) Bigger pizzas are heated before smaller ones.

Question 11:

Refer to the plot of temperature versus time (Fig. 11.2) showing the changes in the state of ice on heating (not to scale).

Which of the following is correct?

(a) The region AB represents ice and water in thermal equilibrium.

(b) At B water starts boiling.

(c) At C all the water gets converted into steam.

(d) C to D represents water and steam in equilibrium at boiling point.

Question 12:

A glass full of hot milk is poured on the table. It begins to cool gradually. Which of the following is correct?

(a) The rate of cooling is constant till milk attains the temperature of the surrounding.

(b) The temperature of milk falls off exponentially with time.

(c) While cooling, there is a flow of heat from milk to the surrounding as well as from surrounding to the milk but the net flow of heat is from milk to the surrounding and that is why it cools.

(d) All three phenomenon, conduction, convection and radiation are responsible for the loss of heat from milk to the surroundings.