Question

A wire of length $I$, area of cross-section $A$ and Young's modulus of elasticity $Y$ is stretched by a longitudinal force $F$. The change in length is $\Delta l$. Match the following two columns.

Answer 1

Since as $F$ is increased stress = $F/A$ will increase and therefore, $\Delta l$ will increase.
A->1,2

Now when $l$ is increased then since strain will be same, therefore, $\Delta l/l$ will be constant, therefore,$\Delta l$ will increase.
B->1

Area is increased then stress will decrease, therefore, strain will decrease because $stress/strain=$ Y$=constant$
therefore, $\Delta l$ will decrease.
C->3,4

If $Y$ is increased since $Stress/strain=constant$

Therefore, either stress will increase or strain will decrease or both But since $F$ is given therefore either area will decrease or $\Delta$ will decrease.
D->3