Question

The dimensions of four wires of the same material are given below. In which wire, the increase in length will be maximum : 

(a) length 50 cm, diameter 0.5 mm 

(b) length 300 cm, diameter 3 mm 

(c) length 200 cm, diameter 2 mm 

(d) length 100 cm, diameter 1 mm

Answer 1

Correct option (a) length 50 cm, diameter 0.5 mm

Explanation:

From the law of Young’s modulus

Y = FL /Al

where F = force acting on the wire 

L = initial length of the wire 

l = extention in the length of wire 

A = area of the cross hyphen section of wire