A steel wire and a copper wire are joined end to end having equal cross section. The elongation of two wires are found to be equal under tension. What is the ratio of the length of the steel to the length of copper wire?
(Young modulus of steel = 2 × 1011 Nm-2 and
Young modulus of copper = 1.1 × 1011 Nm-2)
1
1 ∶ 2
2
2 ∶ 1
3
20 ∶ 11
4
11 ∶ 20