Question

Calculate the value of the electric current $\left(i\right)$ in the following circuit.

• A. $1.46A$
• B. $0.46A$
• C. $3.46A$
• D. $2.46A$

Answer 1

The correct option is C $3.46A$

Given:
Source voltage, $V=12V$
Resistances, $R_1=7.4\Omega$, $R_2=15.6\Omega$ and $R_3=11.2\Omega$
The current in the circuit is same as the current through the effective resistance of the circuit.
Effective resistance in parallel, $\frac{1}{R_{eff}}=\frac{1}{R_1}+\frac{1}{R_2}+\frac{1}{R_3}$
$⟹\frac{1}{R_{eff}}=\frac{1}{7.4}+\frac{1}{15.6}+\frac{1}{11.2}$
$⟹\frac{1}{R_{eff}}=0.2885{\Omega }^{-1}$ -----(1)
Potential difference,
$V=i{R}_{eff}$ ------ (2) (ohm's law)
where $i$ is the electric current.
From (1) & (2)
$⟹i=\frac{V}{R_{eff}}=12\times 0.2885$

$⟹i=3.46228A$