Question

Derive expression for resistance in series and parallel​

Answer 1

Answer:

According to Ohm's law, the voltage drop, V, across a resistor when a current flows through it is calculated by using the equation V=IR, where I is current in amps (A) and R is the resistance in ohms (Ω). This implies that the total resistance in a series is equal to the sum of the individual resistances.

Explanation:

Answer 2

let R1,R2,R3 be three resistors combined in series with a p.d( V )and current passing through it be(1)

V1=I*R1

V2=I*R2

V3=1*R3

(V1+V2+V3)=l(R1+R2+R3) replacing V1,V2,V3 by (V)

V/I=R1+R2+R3

Req=R1+R2+R3

prooved

derivation of parallel resistance

let R1,R2,R3 be three resistances connected in parallel with a p.d(V)

1=V/R1

12=V/R2

13=V/R3

11+12+13=V/R1+V/R2+V/R3

replacing 1+12+13 by I

l=V(1/R1+1/R2+1/R3)

I/V= 1/R1+1/R2+1/R3

1/V/=1/R1+1/R2+1/R3

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

prooved