Respuesta :

As per the question, the resistor system contains two resistors.

The two resistors are denoted as [tex]r_{1}\ and\ r_{2}\ respectively[/tex]

We are asked to calculate the effective resistance in terms of  [tex]r_{1}\ and\ r_{2}\ respectively[/tex]

The two resistors can be connected in two ways.

CASE-1: Let the resistors are connected in series.

When the resistors are connected in series, the effective resistance is the algebraic sum of the individual resistors.

Hence, the effective resistance  [tex]r= r_{1} +r_{2}[/tex]  [ans]

CASE-2: Let the resistors are connected in parallel.

The effective resistance is calculated as follows-

                                     [tex]\frac{1}{r}= \frac{1}{ r_{1}}+ \frac{1}{r_{2}}[/tex]

                                            [tex]=\frac{r_{1}+ r_{2}} {r_{1} r_{2}}[/tex]

                                   ⇒  [tex]r =\frac{r_{1} r_{2}} { r_{1} +r_{2}}[/tex]  [ans]