JEE Main 2026 Physics question
The temperature of a metal strip having coefficient of linear expansion α is increased from T₁ to T₂ resulting in increase of its length by ΔL₁. The temperature is further increased from T₂ to T₃ such that the increase in its length is ΔL₂. Given T₃+T₁=2T₂ and T₂−T₁=ΔT, the value of ΔL₂ is .
Answer: (D)
Solution
T₃−T₂ = T₂−T₁ = ΔT (from the given condition). ΔL₁=L₁αΔT, and ΔL₂=L₂α(T₃−T₂)=L₁(1+αΔT)·αΔT = ΔL₁(1+αΔT).