Question

Calculate the potential difference across a $100\Omega$ resiter before the voltmeter is connected.

Answer 1

Current across the whole cicuit is,

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

$I=\frac{84}{100+200}$

$=\frac{84}{300}$

$=0.28A$

the potential difference across the $100\Omega$ resistor is,

$V=IR$

$V=0.28\times 100$

$=28V$