Question

Three bulbs, each having a resistance of 180 $\Omega$, are connected in parallel to an ideal battery of emf 60 V. Find the current delivered by the battery when (a) all the bulbs are switched on, (b) two of the bulbs are switched on and (c) only one bulb is switched on.

Answer 1

$\left(a\right)R_{eff}=\frac{180}{3}=60\Omega$

$i=\frac{60}{60}=1A$

(b) $R_{eff}=\frac{180}{2}=90\Omega$

i =$\frac{60}{90}=0.67A$

(c)$R_{eff}=180\Omega$

i =$\frac{60}{180}=0.33A$