Physics · Units, Dimensions & Error Analysis

JEE Main 2025 — 8 April, Evening Shift — Question 55

A quantity QQ is formulated as X−2Y+32Z−25,X,YX^{-2} Y^{+\frac{3}{2}} Z^{-\frac{2}{5}}, X, Y and ZZ are independent parameters which have fractional errors of 0.1,0.20.1,0.2 and 0.5 , respectively in measurement. The maximum fractional error of QQ is

  1. Option A:

    0.1

  2. Option B:

    0.6

  3. Option C:

    0.7

    Correct
  4. Option D:

    0.8

Answer: C

Step-by-step solution

ΔQQ=−2(±Δx)x+32(±Δy)y−25(±Δz)z\frac{\Delta Q}{Q}=-2 \frac{( \pm \Delta x)}{x}+\frac{3}{2} \frac{( \pm \Delta y)}{y}-\frac{2}{5} \frac{( \pm \Delta z)}{z}

For maximum fractional error ΔQQ=2Δxx+32Δyy+25Δzz=2×0.1+32×0.2+25×0.5\begin{aligned} \frac{\Delta Q}{Q} & =\frac{2 \Delta x}{x}+\frac{3}{2} \frac{\Delta y}{y}+\frac{2}{5} \frac{\Delta z}{z} \\ & =2 \times 0.1+\frac{3}{2} \times 0.2+\frac{2}{5} \times 0.5 \end{aligned} =0.7=0.7

Answer key and solution verified before publishing.

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Exam
JEE Main 2025
Subject
Physics
Chapter
Units, Dimensions & Error Analysis
Topic
Significant Figures and Error Analysis