Question

The resistance R =$\frac{V}{i}$where V= 100 $\pm$5 volts and i = 10 $\pm$0.2 amperes. What is the total error in R

• A. 5%
• B. 7%
• C. 5.2%
• D. $\frac{5}{2}$%

Answer 1

Answer: (B)

7%

Answer 2

$R = \frac{V}{I}$ $\therefore$ ${\left( \frac{\Delta R}{R} \times 100 \right)\frac{\Delta V}{V}\frac{\Delta I}{I}}_{\max}$

$= \frac{5}{100} \times 100 + \frac{0.2}{10} \times 100$ $= (5 + 2)\%$ = 7%