JEE Main 2019PhysicsThermal Properties of MatterEasyMCQ

JEE Main 2019 — Thermal Properties of Matter Question with Solution

JEE Main 2019 (12 Apr Shift 1)

Question

At 40°C, a brass wire of 1 mm radius is hung from the ceiling. A small mass, M is hung from the free end of the wire. When the wire is cooled down from 40°C  to 20°C it regains its original length of 0.2 m. The value of M is close to:
(Coefficient of linear expansion and Young’s modulus of brass are 10-5/°C and 1011 N/m2, respectively; g=10 m s-2 )

Choose an option

Show full solutionCorrect option: D
Correct answer
D9 kg

Step-by-step explanation

Mg=AYlΔl
Δll=αΔT
Mg=AYαΔT
M=AYαΔTg=π×0.0012×1011×10-5×2010=2π
Closest value of M is 9 kg.

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About this question

This is a previous-year question from JEE Main 2019, covering the Thermal Properties of Matter chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.