Question

A current carrying conductor obeys $Ohm ^{\prime} s$ law $(V=R I)$. If the current passing through the conductor is $I=(5 \pm 0.2) A$ and voltage developed is $V=(60 \pm 6) V$, then find the percentage of error is resistance, $R$

• A. 18
• B. 6
• C. 14
• D. 2

Answer 1

Answer: (C)

Given, current passing through the conductor,
$I=(5 \pm 0.2) A , \Delta I=0.2 A$
Voltage developed,
$ V =(60 \pm 6) V $
$\Rightarrow \Delta V =6 V$
By Ohm's law,
$V=R I $
$R=\frac{V}{I}$
$\therefore \frac{\Delta R}{R} =\frac{\Delta V}{V}+\frac{\Delta I}{I} $
$=\frac{6}{60}+\frac{0.2}{5} $
$=0.1+0.04$
$\frac{\Delta R}{R} =0.14 $
$\therefore \frac{\Delta R}{R} \times 100 =0.14 \times 100=14 \%$