Two rods one made of copper and other made of steel of the same length and same cross sectional area are joined together. The thermal conductivity of copper and steel are 385 J s − 1 K − 1 m − 1 and 5

Question

Two rods one made of copper and other made of steel of the same length and same cross sectional area are joined together. The thermal conductivity of copper and steel are 385 J s − 1 K − 1 m − 1 and 50 J s − 1 m − 1 respectively. The free ends of copper and steel are held at 10 0 ∘ C and 0 ∘ C respectively. The temperature at the junction is, nearly:NEET 2022 (Phase 2)

TestHub · Accepted Answer

As per question, we have; ​ θ = ? As K = A Δ t Q d ​ , where, K = thermal conductivity Q = amount of heat transferred d = distance between two planes A = area of surface, and Δ T = difference in Temp. Δ t Δ Q ​ = l 385 × A × ( 10 0 ∘ C − θ ) ​ = l 50 × A × ( θ − 0 ∘ C ) ​ ⇒ 385 ( 10 0 ∘ C − θ ) = 50 ( θ − 0 ∘ C ) ⇒ θ = 88. 5 ∘ C ​

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