Question

A Copper wire and steel of the same diameter and length are connected end to end and a force is applied, which stretches their combined length by 1 cm. The two wires will have
A. the same stress
B. different stress
C. the same strain
D. different strain

Answer 1

Correct Answer - A::D
Consider the diagram where a deforming force F is applied to the combination.
For steel wire, `Y_("steel")=("Stress")/("Strain")=(F//A)/("Strain")`

where F is tension in each wire and A is cross-section area of each wires.
As F and A are same for both the wire, hence, stress will be same for both the wire.
`("Strain")_("Steel")=("Strain")/(Y_("steel")),("Strain")_("copper")=("Stress")/(Y_("Copper"))`
As, `" "Y_("steel")neY_("copper")`
Hence, the two wires will have differents strain.