Two different wires having lengths and

PHYSICS · Single correct · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter

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)] (1)

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

(2)

2\sqrt{\beta_1 \beta_2}

(3)

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

(4)

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