NTA Abhyas JEE Main2020PhysicsThermal Properties of MatterPractice
Two rods, one of aluminium and the other made of steel, having initial lengths l 1 and l 2 are connected together to form a single rod of length l 1 + l 2 . The coefficients of linear expansion for aluminium and steel are α a and α s respectively. If the length of each rod increases by the same amount when their temperature is raised by t ° C , then find the ratio l 1 l 1 + l 2
Options
- Aα s α a
- Bα a α s
- Cα s ( α a + α s )
- Dα a ( α a + α s )
Correct answer
C. α s ( α a + α s )
Step-by-step solution
Given, Δ l 1 = Δ l 2 or, l 1 α a t = l 2 α s t ∴ l 1 l 2 = α s α a or, l 1 l 1 + l 2 = α s α a + α s