Question

A slab of material has area A, thickness L, and thermal conductivity k. One of its surfaces (P) is maintained at temperature T1 and the other surface (Q) is maintained at a lower temperature T2. The rate of heat flow by conduction from P to Q is:

A) (k * A * (T1 - T2)) / L
B) (k * L * (T1 - T2)) / A
C) (A * (T1 - T2)) / (k * L)
D) (T1 - T2) / (k * A * L)

Answer 1

The rate of heat flow by conduction through a slab is given by the formula Q/t = (k × A × (T1 - T2)) / L, making option A the correct answer.

Step-by-step explanation:

The student's question pertains to the rate of heat flow by conduction through a slab of material with a given thermal conductivity (k), surface area (A), and thickness (L).

The formula to calculate this rate of heat flow is Q/t = k × A × (T1 - T2) / L, where T1 is the higher temperature maintained on one side of the slab, and T2 is the lower temperature on the other side.

Thus, the correct answer to the student's question is A) (k × A × (T1 - T2)) / L.

This formula indicates that the heat flow rate is directly proportional to the thermal conductivity of the material, the surface area through which heat is being transferred, and the difference in temperature across the slab. It is inversely proportional to the thickness of the slab. Option A. is the correct one.