Question

a) Three resistors of resistances $2\Omega ,3\Omega$ and $4\Omega$ are combined in series. What is the resistance of the combination?
b) If this combination is connected to a battery of emf 10 V and negligible internal resistance, obtain the potential drop across each resistor.

Answer 1

(a) : Equivalent resistance of series combination $R_{eq}=R_1+R_2+R_3$

$\therefore$ $R_{eq}=2+3+4$

$⟹$ $R_{eq}=9\Omega$

(b) : Current flowing through the circuit $I=\frac{E}{R_{eq}}$

$\therefore$ $I=\frac{10}{9}=1.11$ A

Voltage across $R_1$, $V_1=I{R}_1$

$\therefore$ $V_1=1.11\times 2=2.22$ V

Voltage across $R_2$, $V_2=I{R}_2$

$\therefore$ $V_2=1.11\times 3=3.33$ V

Voltage across $R_3$, $V_3=I{R}_3$

$\therefore$ $V_3=1.11\times 4=4.44$ V