Two rods of different materials having coefficients of thermal expansion α 1 , α 2 and…

Two rods of different materials having coefficients of thermal expansion α₁, α₂ and Young’s modulli Y₁, Y₂ respectively are fixed between two rigid massive walls. The rods are heated such that they undergo the same increase in temperature. There is no bending of the rods. If α₁ : α₂ = 2 : 3, the thermal stresses developed in the two rods are equal provided Y₁ : Y₂ is equal to :
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