Question

3 resistors of resistance R1,R2,R3 are connected in i)parallel ii)series. write expression for equivalent resistance of combination in each case

Answer 1

In series:

Since, in series combination the values of resistances are added, the value of equivalent resistance is larger than the largest value of resistance in the combination of resistors.

$R_{eq} = R_{1} + R_{2} + R_{3}$

In parallel:

In parallel connection, the value of equivalent resistance is smaller than the smallest value of resistance in the combination of resistors.

The expression for equivalent resistance in parallel combination will be,

$\frac{1}{R_{eq}} = \frac{1}{R_{1}} + \frac{1}{R_{2}} + \frac{1}{R_{3}}\\\\R_{eq} = \frac{R_{1}R_{2}R_{3}}{R_{1}R_{2}+R_{2}R_{3} + R_{1}R_{3}}$

Answer 2

Hello Guys!!!!

In Series

Req=R1+R2+R3

In Parallel

Req=1/R1+1/R2+1/R3

Thanks