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 12

A composite wall consists of two layers: Layer 1 has k₁ = 0.5 W·m^-1·K^-1, thickness d₁ = 0.1 m; Layer 2 has k₂ = 0.2 W·m^-1·K^-1, thickness d₂ = 0.2 m. What is the equivalent thermal conductivity if the layers are in series?

A metal rod of length 2 m and cross-sectional area 0.01 m² has its ends maintained at 100°C and 0°C. If the thermal conductivity of the rod is 200 W·m^-1·K^-1, calculate the rate of heat flow.

A refrigerator wall is made of a material with k = 0.04 W·m^-1·K^-1, thickness 0.05 m, and area 1.5 m². If the temperature difference across the wall is 20 K, calculate the heat loss per second.

A rod is made of two materials, A and B, joined end to end. If k_A = 100 W·m^-1·K^-1 and k_B = 50 W·m^-1·K^-1, and both sections are of equal length and area, which section will have a greater temperature gradient?

A slab of thickness 0.05 m and area 2 m² has a temperature difference of 40 K across it. If the rate of heat transfer is 320 W, what is the thermal conductivity of the material?

A wall is made of a material with thermal conductivity 0.8 W·m^-1·K^-1, thickness 0.2 m, area 10 m², and temperature difference across it is 30 K. Calculate the rate of heat transfer through the wall.

A wall is made of two materials in parallel, each with area 2 m², thickness 0.1 m, and thermal conductivities 0.5 and 1.0 W·m^-1·K^-1. What is the total rate of heat transfer if the temperature difference is 10 K?

Define thermal conductivity and state its SI unit.

Describe the difference between thermal conductivity and heat capacity.

Describe the effect of increasing temperature on the thermal conductivity of metals and non-metals.

Explain why cooking utensils are often made with metal bottoms and plastic 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 rate of heat transfer through a slab is given by the formula Q = kA(ΔT)/d. What does each symbol represent?

A copper rod and an aluminum rod, each of length 1 m and cross-sectional area 0.001 m², are joined end to end. The free end of the copper rod is kept at 150°C and the free end of the aluminum rod is kept at 50°C. If the thermal conductivities of copper and aluminum are 400 W·m^-1·K^-1 and 200 W·m^-1·K^-1 respectively, calculate the temperature at the junction of the two rods in steady state.

A cylindrical rod of length 0.5 m and radius 0.01 m is made of a material with thermal conductivity 150 W·m^-1·K^-1. If the temperature difference between its ends is 80 K, calculate the rate of heat transfer through the rod.

A material has a thermal conductivity of 0.12 W·m^-1·K^-1. If a slab of this material with thickness 0.03 m and area 0.8 m² is subjected to a temperature difference of 25 K, calculate the amount of heat transferred in 10 minutes.

A steel plate of thickness 0.02 m and area 0.5 m² is used as a heat shield. If the temperature on one side is 600 K and on the other side is 300 K, and the thermal conductivity of steel is 50 W·m^-1·K^-1, calculate the heat flux through the plate.

A wall is constructed using three layers of different materials in series. The thicknesses are 0.05 m, 0.10 m, and 0.15 m, and the thermal conductivities are 0.8, 0.04, and 0.2 W·m^-1·K^-1 respectively. If the area of the wall is 5 m² and the temperature difference across the wall is 40 K, calculate the total rate of heat transfer through the wall.