Question

Find the final temperature of a copper rod. Whose area of cross
section changes from 10 m2 to 11 m2 due to heating. The
rod is initially kept at 90 K. (Coefficient of superficial expansion is
0.0021 / K).
​

Answer 1

use formula, $A=A_0(1+\beta\Delta T)$

where A is area of material rod at final temperature, $A_0$ is area of material rod at initial temperature, β is coefficient of superficial expansion and ∆T is change in temperature.i.e., $(T-T_0)$

given, $A_0$ = 10 m² , A = 10m² , β = 0.0021/K and $T_0=90K$

so, 11 = 10[1 + (T - 90) × 0.0021]

⇒11 = 10 + 10 × (T - 90) × 0.0021

⇒11 - 10 = (T - 90) × 0.021

⇒1/0.021 = T - 90

⇒47.62 = T - 90

⇒ T = 137.62K

Answer 2

Answer:

Explanation:

By using the formula for coefficient of superficial expansion we get: