Q: A steel bridge is 500 m long at 20°C. If the temperature rises to 40°C, what is the increase in length? (Coefficient of linear expansion for steel $$\alpha = 1.2 \times 10$$^{-5}$$ \, \text{K}^{-1})$$

$$\Delta L = 0.15 \, \text{m}$$

Q: A granite ball of radius 2.00 m and emissivity 0.45 is heated to 135°C. If the ambient temperature is 25°C, what is the net power radiated by the ball? ($$\sigma = 5.67 \times 10$$^{-8}$$ \, \text{W}/\text{m}^2 \cdot \text{K}^4)$$

$$2.54 \times 10^4$ \, \text{W}$$

Question 1

Which of the following best describes the concept of temperature in thermodynamics?

Accepted Answer

Temperature is a measure of the average kinetic energy of the constituents of a system.

Question 2

A steel bridge is 500 m long at 20°C. If the temperature rises to 40°C, what is the increase in length? (Coefficient of linear expansion for steel $$\alpha = 1.2 	imes 10$$^{-5}$$ \, 	ext{K}^{-1})$$

Accepted Answer

$$\Delta L = 0.15 \, 	ext{m}$$

Question 3

Which of the following statements about heat is correct?

Accepted Answer

Heat is energy in transit due to a temperature difference.

Question 4

A 100 g block of aluminum ($$c = 900 \, 	ext{J}/	ext{kg} \cdot 	ext{K}) at 80$$°C is placed in 200 g of water at 20°C ($$c = 4190 \, 	ext{J}/	ext{kg} \cdot 	ext{K}). $$What is the final equilibrium temperature? (Assume no heat loss to the environment.)

Accepted Answer

About 24°C

Question 5

Which equation correctly relates Celsius and Fahrenheit temperatures?

Accepted Answer

$$T_F = \frac{9}{5} T_C + 32$$

Question 6

Why is absolute zero considered unreachable in practice?

Accepted Answer

Because it is impossible to remove all energy from a system due to quantum mechanical effects.

Question 7

A 75-g ice cube at 0°C is placed in 825 g of water at 25°C in a well-insulated bottle. What is the final temperature when thermal equilibrium is reached? ($$L_f = 3.34 	imes 10^5$ \, 	ext{J}/	ext{kg}$$, $$c_{water} = 4190 \, 	ext{J}/	ext{kg} \cdot 	ext{K})$$

Accepted Answer

16.3°C

Question 8

Which of the following best explains why water is used as a coolant in car engines?

Accepted Answer

Water has a high specific heat capacity, so it can absorb a lot of heat without a large temperature increase.

Question 9

Which formula gives the amount of heat required to change the temperature of a mass $$m of a $$substance by $$\Delta T$$?

Accepted Answer

$$Q = mc\Delta T$$

Question 10

A granite ball of radius 2.00 m and emissivity 0.45 is heated to 135°C. If the ambient temperature is 25°C, what is the net power radiated by the ball? ($$\sigma = 5.67 	imes 10$$^{-8}$$ \, 	ext{W}/	ext{m}^2 \cdot 	ext{K}^4)$$

Accepted Answer

$$2.54 	imes 10^4$ \, 	ext{W}$$

Question 11

Which of the following is NOT a mechanism of heat transfer?

Accepted Answer

Compression

Question 12

During a phase change, such as melting or boiling, what happens to the temperature of a substance as heat is added?

Accepted Answer

The temperature remains constant.

Question 13

Which equation describes the heat current $$H$$ through a wall of area $$A$$, thickness $$L$$, and thermal conductivity $$k$$, with a temperature difference $$T_H - T_C$$ across it?

Accepted Answer

$$H = kA \frac{T_H - T_C}{L}$$

Question 14

A 25.0 g sample of steam at 100°C is condensed and cooled to 34.0°C. How much heat is released? ($$L_v = 2.26 	imes 10^6$ \, 	ext{J}/	ext{kg}$$, $$c_{water} = 4190 \, 	ext{J}/	ext{kg} \cdot 	ext{K})$$

Accepted Answer

61.9 kJ

Question 15

Which of the following best describes the Kelvin temperature scale?

Accepted Answer

It is an absolute scale with zero at the point where average kinetic energy is zero.

Question 16

Which property of a material determines how much its length changes with temperature?

Accepted Answer

Coefficient of linear expansion ($$\alpha)$$

Question 17

If a thick object increases in temperature by $$\Delta T$$, which equation gives the change in its volume?

Accepted Answer

$$\Delta V = \beta V_0$ \Delta T$$

Question 18

Which of the following statements about the concept of heat is emphasized in thermodynamics?

Accepted Answer

Heat is only meaningful as energy in transit due to a temperature difference.

Question 19

A bimetallic strip bends when heated because:

Accepted Answer

The two metals have different coefficients of linear expansion.

Question 20

Which of the following best describes the role of the Stefan-Boltzmann constant ($$\sigma) in $$heat transfer by radiation?

Accepted Answer

It relates the power radiated by a blackbody to its temperature.

Chapter 14: Temperature & Heat – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards