MHT CET20228 Aug 2022Evening ShiftPhysicsThermal Properties of MatterActual
Two metal rods P and Q have same length and same temperature difference between their ends. Their thermal conductivities are K₁ and K₂ , also cross-sectional areas A₁ and A₂ respectively. If the rate of flow of heat through rod Q is three times that in rod P , then
Options
- AK ₁ ~A ₁=3 ~K ₂ ~A ₂
- B3 ~K ₁ ~A ₁= K ₂ ~A ₂
- C3 ~K ₁ ~A ₁=2 ~K ₂ ~A ₂
- D2 ~K ₁ ~A ₁=3 ~K ₂ ~A ₂
Correct answer
B. 3 ~K ₁ ~A ₁= K ₂ ~A ₂
Step-by-step solution
Concept: the rate of heat flow through the rod is given by Q = KA l Where K is the conductivity, Q is the temperature difference across, A is the area of cross-section and 1 is the length of the rod. aligned & ( Q )_ Q =( Q )_ P & K ₂ ~A ₂ l = 3 ~K ₁ ~A ₁ l & K ₂ ~A ₂=3 ~K ₁ ~A ₁ aligned