KEAM 2015 Physics and Chemistry Paper

Given, r1:r2=1:2 and l4=8
In the first condition (cross-section area)
A1=πr12....(i)
In the second condition,
(cross-section area) A2=πr22.....(ii)
On dividing Eq. (i) by Eq. (ii), we get
‌

A1

A2

=‌

I12

I22

or ‌

A1

A2

=(‌

1

2

)2=‌

1

4

Stress 1: Stress 2=4:1
Strain 1: Strain 2=4:1
‌

l

l2

=‌

4

1

⇒l1=4l2
Increase in length of B,
l2=‌

l

n

=‌

8

2

=2mm