JEE · NEET Previous Year Question

A 3 m long wire of radius 3 mm shows an extension of 0.1 mm when loaded vertically by a mass of 50 kg in an experiment to determine Young's modulus. The value of Young's modulus of the wire as per this experiment is , where the value of is: (Take )

Topic: JEE PYQ

Answer: D. Full step-by-step solution below.

  1. A2.5
  2. B25
  3. C10
  4. D5

Correct answer: D

Solution

(d)
Let's break down the solution step by step:
First, note the given values:
Length of the wire,
Radius of the wire,
Extension of the wire,

Mass attached,
Acceleration due to gravity,
The force (weight) acting on the wire is:

Next, calculate the cross-sectional area, , of the wire:

Young's modulus, , is given by:

Substitute the values into the formula:

Simplify step by step:
Multiply in the numerator:

Multiply in the denominator:

Cancel the common factor in the numerator and denominator:

Divide 450 by 9:

The problem states that Young's modulus can be expressed as . Here we have:

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