Question

state and explain ohms law. Mention condition under which is applicable.

Answer 1

Ohm's Law:
It states that the current through any two points of the conductor is directly proportional to the potential difference applied across the conductor provided that the physical conditions remains constant.
Unit:
It is measured in ohm represented as Ω.
Explanation:
When an electric potential difference is applied across the conductor, the current passes through it. Here some of the current is apposed by the resistance of the conductor in the circuit. Thus Ohm's Law is the relation between current, voltage and resistance.
According to Ohm's Law:
V α I
V = I R
Where  R (resistance) is the constant or proportionality.
Ohm's Law is applicable only if all the physical conditions for example temperature, material or dimensions of the wire remain constant.

Answer 2

Ohm's law:

According to Ohm's law :
At constant temperature the current flowing through a conductor is directly proportional to the potential difference across its ends.

If I is the current flowing through a conductor and V is a potential difference or voltage across it ends then according to Ohm's law:

I ∝ V

[At constant temperature]

V ∝ I

V = R × I

Where R is a constant called resistance of the conductor.
The value of this constant depends on the nature ,length ,area of cross section and temperature of the conductor.

V/I = R

Here,

V = potential difference
I= current
R= resistance (which is a constant)


I = V/R

From this relation

1.The current is directly proportional to potential difference.

2. The current is inversely proportional to resistance.

If the potential difference across the ends of a conductor is doubled the current flowing through it also gets doubled and if the potential difference is Halved the current also gets halved.

If the resistance is doubled the current gets halved and if the resistance is Halved the current gets the doubled.

The SI unit of resistance is Ohm which is donated by the symbol Omega(Ω)

1 ohm is the resistance of a conductor such that when a potential difference of 1 volt is applied to its ends a current of 1 ampere flows through it.


The necessary condition for Ohm’s law to be applicable is that temperature must be constant.

==================================================================
Hope this will help you....