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QJEEM23Phb2ce: JEE Main 2023 Physics - Class 11 JEEM23Phb2ce Solution: Young's moduli of the material of wires A and B are in the…

Young's moduli of the material of wires A and B are in the ratio of 1:41: 4 , while its area of cross sections are in the ratio of 1:31: 3 . If the same amount of load is applied to both the wires, the amount of elongation produced in the wires A\mathrm{A} and B\mathrm{B} will be in the ratio of

[Assume length of wires A and B are same]

Multiple Choice Options

  • A 1:12
  • B 1:36
  • C 12:01
  • D 36:01:00

Step-by-Step Verified Solution

Given the formula for elongation in a material due to a force:

ΔL=FLAY\Delta L = \frac{FL}{AY}

where:

  • F is the force applied,
  • L is the original length,
  • A is the cross-sectional area of the material, and
  • Y is Young's modulus of the material.

The ratio of the elongations in the two wires A and B is given by:

ΔL1ΔL2=F1F2×A2A1×Y2Y1\frac{\Delta L_1}{\Delta L_2} = \frac{F_1}{F_2} \times \frac{A_2}{A_1} \times \frac{Y_2}{Y_1}

Since the same force is applied on both wires (i.e., ( F1/F2F_1/F_2 = 1)), the areas are in the ratio 1:3 (i.e., ( A2/A1A_2/A_1 = 3)), and the Young's moduli are in the ratio 1:4 (i.e., ( Y2/Y1Y_2/Y_1 = 4)), substituting these values into the equation gives:

ΔL1ΔL2=1×3×4=12\frac{\Delta L_1}{\Delta L_2} = 1 \times 3 \times 4 = 12

So, the ratio of the elongations is 12:1, which indicates that wire A will elongate 12 times more than wire B when the same force is applied.

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