NTA Abhyas JEE Main2020PhysicsThermal Properties of MatterPractice
A planar frame is made of thin uniform rods. The length of section AB and EF is l 1 and its coefficient of linear expansion is α 1 . The length of section CD is l 2 and its coefficient of linear expansion is α 2 . CB and DE are of the same length having coefficient of linear expansion α 2 . Points A, B, E and F reside on same line, that is, sections AB and EF overlap. Then the ratio l 1 l 2 for which t
Correct answer
2
Step-by-step solution
For distance between A and F to remain constant, extension in CD = extension in AB + extension in EF ∴           Δ l 2 = 2 Δ l 1     ⇒       l 2 α 2 Δ θ 2 = 2 l 1 α 1 Δ θ Or l 1 l 2 = α 2 2 α 1 n = 2