Hello Ganesh

I will discuss these three important laws one by one as follows :-

Ohm's law:-

It was George Simon Ohm who formulated the Ohm’s law. He stated that the electric current that flows through a wire will be directly proportional to the potential difference across the ends when the temperature remains constant. That constant is nothing but the resistance. The resistance of a material is constant when the temperature remains constant. V = I R. Ohm’s law is considered as one of the most basic law in the field of electronics. Thus
Voltage V = Current * Resistance = I R
Current I = Voltage / Resistance = V / R.

            
            
Resistance R = Voltage / Current = V / I
Coulomb law-:
Charles-Augustin de Coulomb,a French physicist in 1784, measured the force between two point charges and found that the force is inversely proportional to the square of the distance between the charges and directly proportional to the product of charges (magnitudes only).
Generally, the statement, let’s say there are two charges q1and q2.The distance between the charges is ‘r’, and the force of attraction/repulsion between them is ‘F’. Then
F ∝q1q2
F ∝1/r2
F = k q1q2/ r2
where k is proportionality constant and equals to 1/4 πε0,the symbol ε0is called epsilon naught and it signifies permittivity of a vacuum.
The value of k comes 9 × 109Nm2/ C2when we take the S.I unit of value of ε0is
8.854 × 10-12C2N-1m-2
Coulomb also stated that like charges repel each other and unlike charges attract each other. This means charges of same sign will push each other with repulsive forces while charges with opposite signs will pull each other with attractive force.
Biot Savart's law:-
Biot-Savart's law is used to determine the magnetic field at any point due to a current carrying conductor.
This law is although for infinitesimally small conductor yet it can be used for long conductors. In order to understand the Biot-Savart's law, we need to understand the term current-element.
Current element It is the product of current and length
he current element is taken as a vector quantity. Its direction is same as the direction of current.