Question

derive the expression of equivalent resistance when three resistance are connected in parallel combination​

Answer 1

Hi.....

In parallel combination,

each resistor's one end is connected to the positive terminal while the other end is connected to a negative terminal.

The potential difference across each resistance is the same and the current passing through them is different.

V = V1 =V2=V3

I  = I1+ I2+I3

Current throught each resistor will be:

I1= V/R1 , I2 = V/R2 = I3 = V/R3

I = V (1/R1+ 1/R2+1/R3)  

In case of equivalent resistance I=V/Re

V/Re =  V (1/R1+ 1/R2+1/R3)

So the equivalent resistance is the sum of all resistances

  1/Re = 1/R1+ 1/R2+1/R3

Thank You!!