Two wires 1 and 2 of the same cross sectional area `A=10mm^2` and the same length but made of different materials are welded together and their ends are rigidly clamped between two walls, as shown in figure. The respective young's moduli and coefficient of linear expansions are `y_1 = 10^9 N//m^2 , y_2 = 2 xx 10^9 N//m^2 , alpha_1 = 6 xx 10^(-4) ""^@C^(-1) , alpha_2 = 3 xx 10^(-4) ""^@C^(-1)` . if temperature of system reduced by `20^@`C then

Find the displacement of the joint

Options

A. 0
B. 10cm
C. 5cm
D. 2cm

Answer

A