Question

If voltage $V=\left(100\pm 5\right)$ volt and current $1=\left(10\pm 0.2\right)A,$ the percentage error in resistance R is

• A. 5.2%
• B. 25%
• C. 7%
• D. 10%

Answer 1

Answer: (C)

Given voltage $V=\left(100\pm 5\right)$ volt, Current $I=\left(10\pm 0.2\right)A$ From Ohms law $V=IR$ $\therefore$ Resistance $R=\frac{V}{I}$ Maximum percentage error in resistance $\left(\frac{\Delta R}{R}\times 100\right)=\left(\frac{\Delta V}{V}\times 100\right)+\left(\frac{\Delta I}{I}\times 100\right)$ $=\left(\frac{5}{100}\times 100\right)+\left(\frac{0.2}{10}\times 100\right)$ $=5+2=7$