__Ohm’s law:__

*Ohm’s law stated that, the electric current flowing through the metallic conductor is directly proportional to the potential difference applied across terminals of conductor provided the physical conditions of conductor remains same.*

∴V α I

∴ V = I R

∴ V/I = R (constant)

The proportionality constant represented as ‘R’ is known as the resistance of material of wire.

**Ex.1)** Metallic conductor of resistance 100 ohm, connected across battery of p.d. 20 V. Find the amount of current flowing through conductor.

Solution: Data

R= 100 Ω

V= 20 V

Formula: V=I.R

On substituting the values in formula,

20=*I*.100

I = 20/100

I = 1/5

I = 0.2 A

**Ex.2) ** Mangnin wire of resistance 5000 ohm carries current of 2 mA .Calculate the potential difference across terminal of conductor

Solution: Data

R= 5000 Ω

I= 2 mA=2×10^{-3} A

Formula: V=I.R

On substituting the values in formula,

V=5000×2×10^{-3}

V=10000×10^{-3}

V=10 V