Question

The resistance $R=V/i$, where $V=100{+}_{5}V$ and $i=10{+}_0.2A$. What is the total error in R?

Answer 1

$R=\frac{V}{i}$

$V=100\pm 5V$

$i=10\pm 0.2A$

$R=\frac{100}{10}=10\Omega$

$\frac{\Delta R}{R}=\frac{\Delta V}{V}+\frac{\Delta i}{i}$

$=\frac{5}{100}+\frac{0.2}{10}$

$=0.05+0.02$

$\frac{\Delta R}{R}=0.07\Rightarrow \Delta R=R\times 0.07=0.7\Omega$

$R=(10\pm 0.7)\Omega$