A copper wire of length 1.0m and a steel wire of length 0.5 m having equal cross-sectional areas are joined end to end. The composite wire is stretched by a certain load which stretches the copper wire by 1 mm. If the Young's modulii of copper and steel are respectively \[1.0\times {{10}^{11}}N{{m}^{-2}}\] and \[2.0\times {{10}^{11}}N{{m}^{-2}}\], the total extension of the composite wire is:

A copper wire of length 1.0m and a steel wire of length 0.5 m having e

1.	A copper wire of length 1.0m and a steel wire of length 0.5 m having equal cross-sectional areas are joined end to end. The composite wire is stretched by a certain load which stretches the copper wire by 1 mm. If the Young's modulii of copper and steel are respectively \[1.0\times {{10}^{11}}N{{m}^{-2}}\] and \[2.0\times {{10}^{11}}N{{m}^{-2}}\], the total extension of the composite wire is:
A.	1.75 mm
B.	2.0 mm
C.	1.50 mm
D.	1.25 mm
Answer» E.