Question

Two 4 Ω resistors are connected in parallel and then connected in series with a 3 Ω resistor. What is the equivalent resistance of this combination?Group of answer choices7 Ω5 Ω1.20 Ω11 Ω

Answer 1

Given,

The resistance connected in parallel, R=4 Ω

The resistor connected in series, r=3 Ω

The equivalent resistance of two given resistors connected in parallel is given by,

$\begin{gathered} R_0=\frac{R\times R}{R+R} \\ =\frac{R}{2} \end{gathered}$

Thus the total equivalent resistance of the given combination of resistance is given by,

$\begin{gathered} R_{eq}=R_0+r \\ =\frac{R}{2}+r \end{gathered}$

On substituting the known values,

$\begin{gathered} R_{eq}=\frac{4}{2}+3 \\ =5\text{ }\Omega \end{gathered}$

Therefore the equivalent resistance of the given combination is 5 Ω

Thus the correct answer is option B.