Embibe Experts Solutions for Chapter: Elasticity, Exercise 1: KEAM 2020

Three thin wires of equal length are suspended from the top of a roof. The respective ratio of their area of cross section is $1: 2: 4$ and Young's modulii is $4: 2: 1,$ then the ratio of their weights to be attached at the other ends to obtain same elongation in them is

A rubber cord of density $d,$Young's modulus $Y$ and length $L$ is suspended vertically. If the cord extends by a length $0.5L$ under its own weight, then $L$ is