Question

Calculate the effective resistance in the following circuit.

• A. $5\Omega$
• B. $12\Omega$
• C. $8\Omega$
• D. $25\Omega$

Answer 1

The correct option is D $25\Omega$

Given:
Voltage$V$ = $6V$
Resistances, $R_1=5\Omega$, $R_2=8\Omega$, $R_3=12\Omega$
Since resistances are connected in series, current $I$ through each resistance is same.
Voltage gets divided among each resistance in series connection.
Let $R_{eff}$ be the effective resistance of the circuit
$\therefore I{R}_{eff}=I{R}_1+I{R}_2+I{R}_3$ (ohm's law)
$\Rightarrow R_{eff}=R_1+R_2+R_3$
$\Rightarrow R_{eff}=5\Omega +8\Omega +12\Omega =25\Omega$
Hence, effective resistance of the ciruit$=25\Omega$