Below you will find a set of 5 conceptual and numerical revision questions selected randomly from lots of questions I have put together covering the material in Chapter 21 "Thermal Properties and Processes". This includes questions on thermal expansion and the transfer of heat by conduction, convection and radiation. When you have finished the quiz, click on the "Submit Quiz" button at the bottom and within seconds it will be automatically graded and the results returned to you!

To select a new set of questions click on the "Reload" or "Refresh" button on your browser. You may find some of the questions duplicated but that's the nature of a random selection. Try it a few times ... it's not fattening and you may learn something!

Many thanks to Mark Wood for producing the quiz-maker code.

Q1: The coefficient of expansion is always positive ...

true
false

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Q2: Two metal rods, one of aluminum and the other of copper, each of length 25 cm and radius 1 cm, are joined to form a composite rod of length 50 cm. Given that the thermal conductivities of aluminum and copper are 237 W/m.K and 401 W/m.K, respectively, and that the "free" end of the rod that is copper is at 100°C and the "free " end of the rod that is aluminum is at 0°C then, assuming no heat losses, the thermal current through the composite rod is

1.87 W
5.34 W
18.7 W
50.4 W

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Q3: If the absolute temperature of an object is doubled, the rate at which it radiates thermal energy

doubles
increases by a factor of 4
increases by a factor of 8
increases by a factor of 16
depends on the emissivity of the object

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Q4: Two bars, A and B, each of length 2.0 m and cross sectional area 1.0 m², are placed end to end as shown in the figure.

Their thermal conductivities are k_A = 339 W/(m.K) and k_B = 837 W/(m.K). The left end of bar A is maintained at 373 K while the right end of B is maintained at 273 K.

How much heat passes the interface between A and B in 5.0 s?

6.0 ¥ 10⁴ J
1.5 ¥ 10³ J
1.2 ¥ 10⁵ J
4.5 ¥ 10⁴ J
3.0 ¥ 10⁴ J

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Q5: A beaker of water is placed on a Bunsen burner. As the lower layers of water are heated, they become less dense and rise. This permits cooler layers to move downward and be heated. Eventually, the water boils. Which method(s) of heat transfer is(are) primarily responsible for boiling the sample?

conduction
convection
radiation
conduction and radiation
conduction and convection

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