A rod of metal X of length 50.0 cm elongates by 0.10 cm when it is heated from `0^(@)C" to "100^(@)C`. Another rod o metal Y of length 80.0 cm elongates by 0.08 cm for the same rise in temperature, A third rod of length 50 cm made by welding pieces of rods X and Y placed end to end, elongates by 0.03 cm when its temperature is raised from `0^(@)C" to "50^(@)C`.
The length of the rod of metal Y in the composite piece is

Options

A. 10 cm
B. 20 cm
C. 30 cm
D. 40 cm

Answer

D

Explanation

`L_(y) =50-L_(x) =50-10=40 cm`.