Class 11 NEET Physics Properties of Matter Questions

Young's modulus,
Y=‌

FL

A∆L

=‌

4FL

πD2∆L

or ∆L=‌

4FL

πD2Y

where F is the force applied, L is the length, D is the diameter and ∆L is the extension of the wire respectively.
As each wire is made up of same material therefore their Young's modulus is same for each wire.
For all the four wires, Y,F(= tension ) are the same.
∴∆L∝‌

L

D2

In (a) ‌

L

D2

=‌

200cm

(0.2cm)2

=5×103cm−1
In (b) ‌

L

D2

=‌

300cm

(0.3cm)2

=3.3×103cm−1
In (c)‌

L

D2

=‌

50cm

(0.05cm)2

=20×103cm−1
In (d) ‌

L

D2

=‌

100cm

(0.1cm)2

=10×103cm−1
Hence, ∆L is maximum in (c).