JEE Main 2019PhysicsMechanical Properties of SolidsEasyMCQ

JEE Main 2019 — Mechanical Properties of Solids Question with Solution

JEE Main 2019 (08 Apr Shift 2)

Question

Young's moduli of two wires A and B are in the ratio  7:4 . Wire A is 2 m long and has radius R. Wire B is 1.5 m long and has radius 2 mm. If the two wires stretch by the same length for a given load, the value of R is close to:

Choose an option

Show full solutionCorrect option: D
Correct answer
D1.7 mm

Step-by-step explanation

Strain = ∆l/l
Stress =F/A
Young’s modulus =StressStrain=F/A∆l/l=FAl∆l
YAYB=lAAAABlB=74
2πrA2πrB21.5=74
rA2=21.5×7×2 mm2
rA=1.7 mm

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About this question

This is a previous-year question from JEE Main 2019, covering the Mechanical Properties of Solids 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.