Ask Questions, Get Answers

Want to ask us a question? Click here
Home  >>  JEEMAIN and AIPMT  >>  Physics  >>  Class11  >>  Thermodynamics
0 votes

A composite bar of length $\;(l_{1} + l_{2})\;$ is made from two bars of length $\;l_{1}\;$ and $\;l_{2}\;$ . Their coefficients of linear expansion $\;\alpha_{1}\;$ and $\;\alpha_{2}\;$ respectively . The effective linear coefficient of composite bar

$(a)\;\large\frac{l_{1} \alpha_{1} - l_{2} \alpha_{2}}{l_{1}-l_{2}}\qquad(b)\;\large\frac{l_{1} \alpha_{1} + l_{2} \alpha_{2}}{l_{1}+l_{2}}\qquad(c)\;\alpha_{1}+\alpha_{2}\qquad(d)\;\large\frac{\alpha_{1} + \alpha_{2}}{2}$

Can you answer this question?

1 Answer

0 votes
Answer : $\;\large\frac{l_{1} \alpha_{1} + l_{2} \alpha_{2}}{l_{1}+l_{2}}$
Explanation :
$\bigtriangleup l_{1} = l_{1} \alpha_{1} \bigtriangleup t$
$\bigtriangleup l_{2} = l_{2} \alpha_{2} \bigtriangleup t$
Total change in length
$\bigtriangleup l_{1} + \bigtriangleup l_{2} = (l_{1} \alpha_{1}+\alpha_{2} l_{2}) \bigtriangleup t $
Therefore , $\;\alpha_{comp}\; = \large\frac{l_{1} \alpha_{1}+l_{2} \alpha_{2}}{l_{1}+l_{2}}$
answered Apr 8, 2014 by yamini.v

Related questions

Ask Question
student study plans
JEE MAIN, CBSE, NEET Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App