Question

The value of current i in the circuit as shown in figure is:

• A. $1.8\text{A}$
• B. $0.8\text{A}$
• C. $0.2\text{A}$
• D. $1.6\text{A}$

Answer 1

The correct option is B $0.8\text{A}$

Three $5\Omega$ resistors are in series. Their total resistance $=15\Omega$. Now it is in parallel with $5\Omega$ resistor, so total resistance,
$\frac{1}{R}=\frac{1}{5}+\frac{1}{15}=\frac{3+1}{15}=\frac{4}{15}$
$R=\frac{15}{4}$
$\therefore I=\frac{V}{R}=\frac{3}{15/4}=\frac{3\times 4}{15}=0.8\text{A}$