Answer:
b. 3 times
Explanation:
Lets take
Coefficient for ordinary glass = α₁
Coefficient for pyrex glass = α₂
Given that α₁ = 3 α₂
Initial length of both glasses are equal = L
Change in the temperature is also same .= ΔT
We know that change in the length given as
ΔL = L α ΔT
Therefore
[tex]\dfrac{\Delta L_1}{\Delta L_2}=\dfrac{L\alpha_1\Delta T}{L\alpha_2\Delta T}[/tex]
[tex]\dfrac{\Delta L_1}{\Delta L_2}=\dfrac{3\alpha_2}{\alpha_2}[/tex]
ΔL₁ = 3ΔL₂
Therefore change in the length of original glass is three time of pyrex glass.
b. 3 times