WAEC Physics 2017 Paper

The resistors are connected both in parallel and series. To calculate the total resistance, we have:

For the parallel connection: $\frac{1}{R} = \frac{1}{1} + \frac{1}{1}$

$\frac{1}{R} = 2 \Rightarrow R = 0.5\Omega$

For the series connection: $R_{total} = (1+0.5)\Omega = 1.5\Omega$

Recall, $V = IR$

$3 = 1.5I \Rightarrow I = \frac{3}{1.5} = 2\mathrm{A}$