JEE Main 2021PhysicsMechanical Properties of SolidsMediumMCQ

JEE Main 2021 — Mechanical Properties of Solids Question with Solution

JEE Main 2021 (25 Jul Shift 1)

Question

Two wires of same length and radius are joined end to end and loaded. The Young's moduli of the materials of the two wires are Y1 and Y2. The combination behaves as a single wire then its Young's modulus is:

Choose an option

Show full solutionCorrect option: B
Correct answer
BY=2Y1Y2Y1+Y2

Step-by-step explanation

In series combination, Δl=ℓ1+ℓ2

Y=F/AΔℓ/ℓ⇒Δℓ=FℓAY

⇒Δℓ∝ℓY

Equivalent length of rod after joining is =2ℓ

As, lengths are same and force is also same in series

Δℓ=Δℓ1+Δℓ2

ℓeqYeq=ℓY1+ℓY2⇒2ℓY=ℓY1+ℓY2

∴ Y=2Y1Y2Y1+Y2

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About this question

This is a previous-year question from JEE Main 2021, 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.