Question

answer this question​

Answer 1

Given data,

the two wires are similar

the two wires are similar hence their initial length and cross section areas are same before elongation

and after elongation,

let ,

area of first wire,A1=4mm²

area of second wire,A2=?

i.e. L is same for each wire

L is same for each wire and same load i.e. same force (F) applied

Calculations,

for first wire,

$y1 = \frac{FL}{lA1} \\ y1 = \frac{FL}{0.1A1}$

for second wire,

$y2 = \frac{FL}{ lA2} \\ y2 = \frac{FL}{ 0.05A2}$

for the similar wires young's modulus is also same

$y1 = y2 \\ \frac{FL}{ 0.1A1} = \frac{FL}{ 0.05A2} \\ 0.05 A2 = 0.1A1 \\ 0.05A2 = 4 \times 0.1 \\ A2 = \frac{0.4}{0.05} \\A2 = 8m {m}^{2}$

hence your answer is option (b)8mm²

hope it helps to you☺️