Question

The resistance $R=\frac{V}{I}$, where $V=100\pm 5$ volts and $I=10\pm 0.3$ amperes. Calculate the percentage error in $R$.

• A. 8 %
• B. 10 %
• C. 12 %
• D. 14 %

Answer 1

The correct option is A 8 %

As given:
$R=\frac{V}{I}$
Using formula for relative error:
$\frac{\Delta R}{R}=\frac{\Delta V}{V}+\frac{\Delta I}{I}$

Here, $V=100V,\Delta V=5V$ and
$I=10A,\Delta I=0.3A$

$\frac{\Delta R}{R}=\frac{5}{100}+\frac{0.3}{10}$
$\frac{\Delta R}{R}=0.05+0.03=0.08$
Percentage Error:
$\frac{\Delta R}{R}\times 100=8$%