JEE Main201910 Jan 2019Morning ShiftPhysicsThermal Properties of MatterActual
A heat source at T = 10 3 K is connected to another heat reservoir at T = 10 2 K by a copper slab which is 1 m thick. Given that the thermal conductivity of copper is 0 .1 W K - 1 m - 1 , the energy flux through it in the steady-state is:
Options
- A65   W   m - 2
- B120   W   m - 2
- C90   W   m - 2
- D200   W   m - 2
Correct answer
C. 90   W   m - 2
Step-by-step solution
Given, Temperature of heat source, T H = 10 3   K , Temperature of heat reservoir, T L = 10 2   K , Conductivity of copper K = 0 . 1   W   K - 1 m - 1 From the equation of steady-state heat flow, d Q d t = K A ∆ T L Heat energy flux can be defined as the rate of heat energy transfer through a given surface. 1 A d Q d t = K × 1000 - 100 1 = 90   W   m - 2