JEE Main202126 Feb 2021Morning ShiftPhysicsThermal Properties of MatterActual
The temperature θ at the junction of two insulating sheets, having thermal resistances R 1 and R 2 as well as top and bottom temperatures θ 1 and θ 2 (as shown in figure) is given by :
Options
- Aθ 1 R 2 - θ 2 R 1 R 2 - R 1
- Bθ 2 R 2 - θ 1 R 1 R 2 - R 1
- Cθ 1 R 2 + θ 2 R 1 R 1 + R 2
- Dθ 1 R 1 + θ 2 R 2 R 1 + R 2
Correct answer
C. θ 1 R 2 + θ 2 R 1 R 1 + R 2
Step-by-step solution
Heat flow rate will be same through both ∴   θ 1 - θ R 1 = θ - θ 2 R 2 R 2 θ 1 - R 2 θ = R 1 θ - R 1 θ 2 θ = R 2 θ 1 + R 1 θ 2 R 1 + R 2