NTA Abhyas JEE Main2020PhysicsThermal Properties of MatterPractice
A partition wall has two layers of different materials A and B in contact with each other. They have the same thickness but the thermal conductivity of layer A is twice that of B . At steady state, if the temperature difference across the layer B is 50   K , then the corresponding temperature difference across the layer A is
Options
- A50 K
- B12 .5 K
- C25 K
- D60 K
Correct answer
C. 25 K
Step-by-step solution
Let T be the junction temperature Here, K A = 2 K B , T - T B = 50 K At the steady state H A = H B ⇒           K A A T A − T L 2 = K B A   T − T B L 2 ⇒ 2 K B T A - T = K B T - T B ⇒ T A - T = T - T B 2 = 50 2 = 25 K