The following four wires are made of same material. Which of these will have the largest extension when the same tension is applied?

Options

A. diameter 1 mm and length 1 m
B. diameter 2 mm and length 2 m
C. diameter 0.5 mm and length 0.5m
D. diameter 3 mm and length 3 m

Answer

C

Explanation

(c) Elongation of the wire
`Deltal=(Fl)/(AY)` or `Deltal prop (l)/(d^(2))" "(because A=(pi)/(4)d^(2))`
Therefore, `Deltal` will be maximum for that wire for which `(1)/(d^(2))` is maximum.