Thermal Conductivity

Physics ⇒ Heat and Thermodynamics

Thermal Conductivity starts at 9 and continues till grade 12. QuestionsToday has an evolving set of questions to continuously challenge students so that their knowledge grows in Thermal Conductivity. How you perform is determined by your score and the time you take. When you play a quiz, your answers are evaluated in concept instead of actual words and definitions used.

See sample questions for grade 11

A copper rod and an iron rod of the same dimensions are heated at one end. Which rod will conduct heat faster and why?

A material has a thermal conductivity of 0.04 W·m^-1·K^-1. Is it more likely to be a conductor or an insulator?

A metal rod of length 2 m and cross-sectional area 0.01 m² has a thermal conductivity of 200 W·m^-1·K^-1. If the temperature difference between its ends is 50 K, calculate the rate of heat transfer through the rod.

A wall is made of two layers: brick (k = 0.6 W·m^-1·K^-1, thickness = 0.2 m) and wood (k = 0.12 W·m^-1·K^-1, thickness = 0.1 m). If the temperature difference across the wall is 30 K and the area is 10 m², calculate the total rate of heat transfer through the wall.

A wall of area 5 m² and thickness 0.25 m has a thermal conductivity of 0.8 W·m^-1·K^-1. If the temperature difference across the wall is 20 K, calculate the rate of heat transfer.

Define thermal conductivity.

Describe how the structure of a material affects its thermal conductivity.

Describe the difference between thermal conductivity and heat capacity.

Explain why cooking utensils are often made with metal but have plastic or wooden handles.

Explain why double-glazed windows are used in cold climates.

Explain why metals are generally better conductors of heat than non-metals.

State Fourier’s law of heat conduction.

The formula for the rate of heat transfer by conduction is Q = k·A·(ΔT/L). What does each symbol represent?

A composite bar is made by joining a copper rod (thermal conductivity k₁ = 400 W·m^-1·K^-1, length = 0.5 m) and an aluminum rod (thermal conductivity k₂ = 200 W·m^-1·K^-1, length = 0.5 m) end to end. If the cross-sectional area is 0.01 m² and the temperature difference across the entire bar is 100 K, calculate the rate of heat transfer through the composite bar.

A metal rod is heated at one end while the other end is kept at a lower temperature. After some time, a steady state is reached. Explain what is meant by 'steady state' in the context of thermal conductivity and describe the temperature profile along the rod.

A refrigerator wall consists of three layers: steel (k = 50 W·m^-1·K^-1, thickness = 0.002 m), polyurethane foam (k = 0.02 W·m^-1·K^-1, thickness = 0.05 m), and plastic (k = 0.2 W·m^-1·K^-1, thickness = 0.003 m). If the area is 2 m² and the temperature difference across the wall is 40 K, calculate the total rate of heat transfer through the wall.

Describe how the thermal conductivity of a gas changes with pressure at constant temperature, and explain the underlying reason.

Explain why the thermal conductivity of diamond is much higher than that of most metals, even though diamond is an electrical insulator.