Answer:
0.08 m
Explanation:
Linear expansivity brass = 2 * 10^-5 C
Linear expansivity = change in length / (initial length * θ)
Change in length = 0.2cm = 0.002m
Initial length = 2m
2 * 10^-5 = 0.002 / (2 * θ)
(2 * 10^-5 * 2θ) = 0.002
4 * 10^-5θ = 0.002
θ = 0.002 / 4 * 10^-5
θ = 2 * 10^-3 / 4 * 10^-5
θ = 0.5 * 10^2
θ = 50°C
For a rod of original length 80m at the same temperature of 50°C
Linear expansivity = change in length / (initial length * θ)
Change in length = dL
2 * 10^-5 = dL / (80 * 50)
2 * 10^-5 * 80 * 50 = dL
160 * 10^-5 * 50 = dL
8000 * 10^-5 = dL
0.08 m = dL
Hence, change in length = 0.08m
