Thermal Conductivity
Physics ⇒ Heat and Thermodynamics
Thermal Conductivity starts at 9 and continues till grade 12.
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See sample questions for grade 10
A 0.5 m thick wall has an area of 10 m² and a thermal conductivity of 0.2 W·m⁻¹·K⁻¹. If the temperature difference across the wall is 30 K, calculate the rate of heat transfer.
A metal rod of length 2 m and cross-sectional area 0.01 m² has a temperature difference of 50 K between its ends. If the thermal conductivity of the metal is 200 W·m⁻¹·K⁻¹, calculate the rate of heat transfer through the rod.
A steel rod and a copper rod of the same dimensions are heated at one end. Which rod will transfer heat to the other end faster?
A wall is made of two layers: brick (k = 0.6 W·m⁻¹·K⁻¹, thickness = 0.2 m) and insulation (k = 0.04 W·m⁻¹·K⁻¹, thickness = 0.1 m). Which layer offers more resistance to heat flow?
Describe how the thermal conductivity of a material affects its use in everyday life.
Describe one practical application of materials with high thermal conductivity.
Explain why air is a poor conductor of heat.
Explain why cooking pots often have plastic or wooden handles.
Explain why metals feel colder than wood at the same temperature.
If a material has a high thermal conductivity, what does this imply about its ability to transfer heat?
If two rods of the same material and length but different cross-sectional areas are subjected to the same temperature difference, which rod will conduct more heat?
State Fourier’s law of heat conduction.
What is thermal conductivity?
Why are double-glazed windows used in cold climates?
A composite wall consists of three layers of different materials, each 0.1 m thick. The thermal conductivities are 0.5 W·m−1·K−1, 0.2 W·m−1·K−1, and 0.1 W·m−1·K−1 respectively. If the temperature difference across the entire wall is 60 K and the area is 2 m2, calculate the total rate of heat transfer through the wall.
A copper rod and an aluminum rod of equal length and cross-sectional area are joined end to end. The free end of the copper rod is kept at 100°C and the free end of the aluminum rod is kept at 0°C. If the thermal conductivities of copper and aluminum are 400 W·m−1·K−1 and 200 W·m−1·K−1 respectively, which rod will have a greater temperature gradient?
Describe how the arrangement of molecules in solids, liquids, and gases affects their thermal conductivity.
Explain why vacuum flasks (thermos flasks) are effective at reducing heat transfer by conduction.
