Question

Please explain me ohm's law in detail with its imp applications.

Answer 1

ohm s law in mathematical form says that ;
V =I×R
it means it is a product of current in a body and the resistance in the body
example can be ::
a resistor.....

Answer 2

Ohm's Law
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The most important basic quantities of electricity are voltage , current and resistance . Ohm's Law shows a simple relationship between these three quantities.

★ Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference across the points . the constant of proportionality is called resistance .
mathematically ,
I = V/R
where I is the current through the conductor , V is the potential difference measured across the conductor and R is the resistance of the conductor .

★ Ohm's Law can also be expressed as

J =bE

where J = current density
E = electric field
b = conductivity = 1/P
P = resistivity

➡ Ohm's law is an assertion that the current through a device is directly proportional to the potential difference applied to the device .

➡ A conducting device obey Ohm's law when the resistance of device is i dependent of the magnitude and polarity of the applied potential difference.

➡ A conducting material obeys Ohm's law when the resisitivtiy of the materail is independent of the magnitude and direction of the applied electric field .

➡ A conducting device obeys Ohm's law only when its physical state remains unchanged.
it means graph between I and V is a straight line passing through origin .
e.g V = RI

hence, slope of graph = R

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microscopic veiw of Ohm's law :-

★ acceleration experienced by electron due to electric field ,
a = F/m = eE/m
where E is electric field , e is charge of one elctron and m is mass of electrons .

★ at any instant , on average drift speed acquired by the electron .
Vd = at = eE/m .t
where t is time of relaxation .

combined both equation ,this can also expressed as ,
E =PJ
P = m/e²nt = constant

where n = no of electrons per unit volume .

★ change in resistance of conductor with change in temperature ,

∆R = R°a∆T
where R° is initial resistance , ∆T change in temperature and a is temperature coefficient .

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application of Ohm's Law :-
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1) the application of Ohm's law that it helps us in determing either voltage , current or resistance of a linear circuit when the other two quantities are known us .

2) it makes power calculation a lot simpler , like when we know the value of the resistance of a particular circuit , we need not to know both current and the votage to calculate the power dissipation , since P = VI ,