Q129 / 155 · WBJEE 2025 · Physics
The resistance $\mathrm{R}=\frac{\mathrm{V}}{\mathrm{I}}$ where $\mathrm{V}=(25 \pm 0.4)$ Volt and $\mathrm{I}=(200 \pm 3)$ Ampere. The percentage error in ' R ' is
- A$1.5 \%$
- B$1.6 \%$
- Correct answerC$3.1 \%$
- D$0.1 \%$
Solution
$\begin{aligned}
& \mathrm{R}=\frac{\mathrm{V}}{\mathrm{I}} \Rightarrow\left(\frac{\Delta \mathrm{R}}{\mathrm{R}}\right)_{\max } \times 100 \%=\left(\frac{\Delta \mathrm{V}}{\mathrm{~V}}+\frac{\Delta \mathrm{I}}{\mathrm{I}}\right) \times 100 \% \\
& =\left(\frac{0.4}{25}+\frac{3}{200}\right) \times 100 \%=3.1 \%
\end{aligned}$
Hence, the correct answer is option: 'C'.