Question

The electric current $\left(I\right)$ flowing through a circuit is directly proportional to the potential difference $\left(V\right)$ in it. When the potential difference is $60$ volts, the electric current is $1.5$ ampere. Find the electric current flowing through the circuit when the potential difference is $100$ volt.

Answer 1

The electric current $\left(I\right)$ flowing through the circuit is directly proportional to the potential difference $\left(V\right)$ in it.
$\therefore$ $V\propto I$
$\therefore$ $V=IR...........\left(1\right)$
where $R$ is the constant of proportionality, the resistance.
Substitute $V=60$ and $I=1.5$ in equation $\left(1\right)$, we get
$60=\left(1.5\right)R$
$\therefore$ $R=\frac{60}{1.5}=40\Omega$
Substitute $R=40\Omega$ in equation $\left(1\right)$, we get
$V=40I........\left(2\right)$
Substitute $V=100$ in equation $\left(2\right)$, we get
$100=40I$
$\therefore$ $I=\frac{100}{40}$
$=2.5$ ampere
When the potential difference is $100$ volt then the electric current flowing through the circuit is $2.5$ ampere.