Page 19 - CHAPTER-1 (Electricity)

CHAPTER 1

ELECTRICITY

Note: The conductors which obey Ohm’s law are called ohmic

conductors while the conductors which do not obey Ohm’s law

are called non-ohmic conductors (e.g. semiconductors).

(i)Graph

The graph between the potential difference V and the corresponding

current I is found to be a straight line. For an Ohmic conductor, this

straight line passes through the origin.

Fig 9:
(ii) Resistance

• It is that property of a conductor by virtue of which it

opposes/resists the flow of charges through it.

• Its SI unit is ohm and is represented by the Greek letter Ω.

• The resistance of a conductor can be given by = .

• It is said to be 1 ohm, if a potential difference of 1 volt across the two

ends of the conductor makes a current of 1 ampere to flow through

it.

i.e. 1 ohm = 1 volt/ 1 ampere

-1
⟹1Ω= 1V =1VA
1A

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