Question

A wire of cross sectional area 3 `mm^(2)` is just stretched between two fixed points at a temperature of `20^(@)C` . Then the tension in the wire when the temperature falls to `10^(@)C` is,
`(alpha =1.2 xx 10^(-5) //""^(@)C, Y=2xx10^(11) N//m^(2))`
A. 80 N
B. 60 N
C. 72 N
D. 50 N

Answer 1

Correct Answer - C
`F=Y alpha A Delta t " " because Y=(F//A)/(l//L)`