Question

Copper of fixed volume V is drawn into wire of length l. When this wire is subjected to a constant force F, the extension produced in the wire is Δl. Which of the following graphs is a straight line?

(a) Δl versus 1/l

(b)   Δl versus l²

(c)  Δl versus 1/l²

(d)  Δl versus l

Answer 1

Correct option (b)   Δl versus l²

Explanation:

As V = Al ...(i)

where A is the area of cross-section of the wire.

Hence, the graph between Δ  artd P is a straight line