Physics · Units, Dimensions & Error Analysis

NEET (UG) 2023 — Question 14

A metal wire has mass (0.4±0.002)g(0.4 \pm 0.002) \mathrm{g}, radius (0.3±0.001)mm(0.3 \pm 0.001) \mathrm{mm} and length (5±0.02)cm(5 \pm 0.02) \mathrm{cm}. The maximum possible percentage error in the measurement of density will nearly be:

  1. Option A:

    1.3%1.3 \%

  2. Option B:

    1.6%1.6 \%

    Correct
  3. Option C:

    1.4%1.4 \%

  4. Option D:

    1.2%1.2 \%

Answer: B

Step-by-step solution

 We know, ρ= Mass  Volume =Mπr2ℓ\text { We know, } \rho=\frac{\text { Mass }}{\text { Volume }}=\frac{M}{\pi r^2 \ell}

Using the concept of errors we know,

Δρρ=ΔMM+2Δrr+Δℓℓ=(0.0020.4+2×0.0010.3+0.025)\begin{aligned} & \frac{\Delta \rho}{\rho}=\frac{\Delta M}{M}+\frac{2 \Delta r}{r}+\frac{\Delta \ell}{\ell} \\ & =\left(\frac{0.002}{0.4}+\frac{2 \times 0.001}{0.3}+\frac{0.02}{5}\right) \end{aligned} Δρρ=0.0156Δρρ%=1.56%≈1.6%\begin{aligned} & \frac{\Delta \rho}{\rho}=0.0156 \\ & \frac{\Delta \rho}{\rho} \%=1.56 \% \approx 1.6 \% \end{aligned}

Answer key and solution verified before publishing.

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Exam
NEET (UG) 2023
Subject
Physics
Chapter
Units, Dimensions & Error Analysis
Topic
Significant Figures and Error Analysis