Question

Two resistors 2 ohm and r ohm are joined parallel to each other. If overall resistance of circuit is 0.5 ohm, calculate the value r. If these resistors are joined with 4 volt battery calculate total current of the circuit?

Answer 1

When two Resistances $R_1$ & $R_2$ are in parallel then

$\frac{1}{R_{eff}}=\frac{1}{R_1}+\frac{1}{R_2}$

$\frac{1}{0.5}=\frac{1}{2}+\frac{1}{r}$

$r=\frac{2}{3}\Omega$

$Current\left(I\right)=\frac{V}{R_{e}ff}=\frac{4}{0.5}=8A$