NTA Abhyas JEE Main2020PhysicsThermal Properties of MatterPractice
Two rods (one semi-circular and other straight) of the same material and of same cross-sectional area are joined as shown in the diagram. The points A and B are maintained at different temperatures. The ratio of the heat transferred through a cross-section of a semi-circular rod to the heat transferred through a cross-section of the straight rod in a given time is
Options
- A2 : π
- B1   :   2
- Cπ : 2
- D3 : 2
Correct answer
A. 2 : π
Step-by-step solution
dQ dt = KA Δ θ l For both rods K, A and Δ θ are same. ∴ dQ dt ∝ 1 l So, dQ / dt semicircular dQ / dt straight = l straight l semicircular = 2 r π r = 2 π