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# Thermal Expansion - JEE Advanced Previous Year Questions with Solutions JEE Advanced Previous Year Questions of Physics with Solutions are available at eSaral. Practicing JEE Advanced Previous Year Papers Questions of Physics will help the JEE aspirants in realizing the question pattern as well as help in analyzing weak & strong areas. Get detailed Class 11th & 12th Physics Notes to prepare for Boards as well as competitive exams like IIT JEE, NEET etc. eSaral helps the students in clearing and understanding each topic in a better way. eSaral is providing complete chapter-wise notes of Class 11th and 12th both for all subjects.       Download eSaral app  for free study material and video tutorials.   Simulator Previous Years JEE Advanced Questions
Q. Steel wire of length ‘L’ at $40^{\circ}$ C is suspended from the ceiling and then a mass ‘m’ is hung from its free end. The wire is cooled down from $40^{\circ}$ to $30^{\circ}$ C to regain its original length ‘L’. The coefficient of linear thermal expansion of the steel is $10^{-5} /^{\circ} \mathrm{C}$, Young’s modulus of steel is 1011 N/m2 and radius of the wire is 1 mm. Assume that L>> diameter of the wire. Then the value of ‘m’ in kg is nearly - [JEE 2011]
Ans. $\Delta L_{1}=\frac{F L}{A Y}=\frac{m g L}{\pi r^{2} Y}=$Increase in length $\Delta L_{2}=L \alpha \Delta T=$ Decrease in length $\Delta L_{1}=\Delta L_{2}$