Physics

Problem

Two different wires having lengths

L_1

and

L_2

, and respective temperature coefficient of linear expansion

eta_1

and

eta_2

, are joined end-to-end. Then the effective temperature coefficient of linear expansion is : [Main Sep. 05, 2020 (II)] a.

\frac{\beta_1 L_1 + \beta_2 L_2}{L_1 + L_2}

2\sqrt{\beta_1 \beta_2}

\frac{\beta_1 + \beta_2}{2}

4 \frac{\beta_1 \beta_2}{\beta_1 + \beta_2} \frac{L_2 L_1}{(L_2 + L_1)^2}