Question

Define resistance. State the factors on which the resistance of a conductor depends. How are
resistances connected in (i) series (ii) parallel. Find the expressions for equivalent resistance
of two different resistors in these two arrangements

Answer 1

Answer:

The property of conductor which opposes the flow of current

FACTORS ON WHICHRESISTANCE DEPEND

1- Resistance is directly proportional to potential difference

R = V

2- Resistance is inversely proportional to electric current

R=1/I

3- Resistance increase with increase in temperature

SERIES COMBINATION

By ohm's law

V=IR

V1=I×R1 ......... 1

V2=I×R2 ......... 2

V3=I×R3 ......... 3

From equation 1, 2 and 3

V=I×R1 + I×R2 + I×R3

V=I(R1+ R2+R3)

Put value of V

IR=I(R1+ R2+R3)

R=R1+ R2+R3

PARALEL COMBINATION

By ohms law

V=IR

V= V1+ V2 +V3

I = V/R

I= V1/R1 ..... 1

I= V2/R2 ......2

I= V3/R3 .....3

From equation 1, 2 and 3

I= V1/R1 +V2/R2 + V3/R3

PUT value of I

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

1/ R= 1/ R1 +1/ R2 +1/ R3