Question

If two rods of length L and 2 L having coefficients of linear expansion a and 2a respectively are connected so that total length becomes 3L, the average coefficient of linear expansion of the composite rod equals –

• A. $\frac{3}{2}$a
• B. $\frac{5}{2}$a
• C. $\frac{5}{3}$a
• D. None of these

Answer 1

Answer: (C)

$\frac{5}{3}$a

Answer 2

(3L)a_effDq = La Dq + 2L(2a)(Dq)

\ a_eff =$\frac{5}{3}$a