Page 18 - CHAPTER-1 (Electricity)

CHAPTER 1

ELECTRICITY

E. Ohm’s law

• This law was given by a German

Physicist Georg Simon Ohm (1787-1854)

in the year 1827.

• It gives a relationship between current I,

flowing in metallic wire and potential

difference V, across its terminals.

• According to this law, the electric

current flowing through any

conductor is directly proportional to

the potential drop applied across its ends, provided that the

physical conditions (such as temperature) remain unchanged.

• If V is the potential difference applied across the ends of a

conductor through which current, I flows, then according to

Ohm’s law,

V∝I [at constant temperature]

V
or, V=IR or I=
R

where, , the constant of proportionality is called resistance of the

conductor at a given temperature.

• From the above formula, we can safely say that current is inversely

proportional to resistance.

• If resistance is doubled, then cu rrent gets halved and if resistance

is halved, then current gets doubled.

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