JEE Advanced Model Paper 8 with solutions for online practice

Tension in elementary section of width dx is T = λxg (λ =

mass

length

)
∴ Extension of length x (=Bc) of wire is
Δx =

x

∫

0

(λxg)

YA

dx =

λx2g

2YA

..... (i)
⇒ Extension in total length of wire l (= AB) is
2Δx =

λl2g

2YA

..... (ii)
∴ From equations (i) and (ii) we get x =

l

√2

AC

PC

=

l−x

x

= (√2 - 1)