Ampere's law: explanation, definition, formula

Definition:-

"Ampere's Law states that magnetic field around a conductor in which electric current is flowing, is directly proportional to the amount of electric current flowing through conductor."

Explanation:

Ampere's law provide us method or formula to calculate magnetic field, produced by electric current.
Just like electric field is directly proportional to the amount of charge, the magnetic field is directly proportional to the amount of electric current from which it is producing.

Formula:-

The most difficult in ampere's law is to derive its equation or make the formula for calculating the magnetic field around a long conducting wire.
So let's start this,
Consider we have long straight conducting wire, when electric current flows through it, the magnetic fields produces around the wire in concentric circle. As shown in below pic.

Every circle is for some specific part of wire and as we move forward in wire, the distance between these circles increases, that mean magnetic field is decreasing. Direction of magnetic field can be found by Fleming's right hand rule.(with direction of current giving)
Now to make the formula, consider there all the parts of wire( which have there magnetic field circuit) having length L and there magnetic field around these parts or elements is B for (every part).

So the equation will become,

And after removing proportionality,

where 𝝁 is the premiability of material or conductor.
B is the magnetic field and delta L is the sum of all length parts and I is the current flowing through the conductor,
sigma shows that the sum of all the length elements or parts with their magnetic field.
Where delta L could be replace by 2πr for particular(single part) length element.
So Then magnetic filed would become,

Faraday'laws of electromagnetic induction

Faraday's have proposed 2 main Laws,
Faraday's law of electromagnetic induction is also known as law of electromagnetism.

Faraday's first law:-

This law is the base of electric generators and motors.

Faraday's law stated that,
"When ever we place a conductor in a magnetic field which is varying with time then there will induced current in the conductor."
And if conductor is connected to a closed circuit then this current will flow through it.

Explanation:-

If a conductor is placed in a field of magnet, if both conductor and magnet are stationary then there will no induced emf in it. But when we will move magnet away from the conductor then magnetic field will change through conductor and then EMF(electromotive force) will induced in conductor. Even if we keep magnet stationary and move conductor then also emf will induced.

Faraday's Second law:-

We use this law often,

"The EMF induced in a coil is equal to the change of flux(by a magnet or something other) with the time. "

Where E is the induced EMF, and N is the number of turns of coil phi is the flux and t is the time.

Explanation:-

When a current is flowing through the coil then there is flux around the coil, when current will change then flux will also changes. And then EMF will induce in a coil.

The induced EMF could increase by:

1.By increasing the number of turns of coil.

2. By increasing rate of changing flux. by changing current rapidly.

3. By using good core on which coil is wound.

Self Induction, definition explanation formula unit

Self Inductance:-

"Self inductance is the property of coil to oppose change in current flowing through it"

Explanation:-

Consider there is a coil wire and current is flowing through it, whenever the current will change flowing through it, then there will induced emf which is known as self induced emf. And its direction will be opposite to the the current flowing through it. If current is increasing then self induced emf will try to decrease or flow in direction opposite to the current. But if current through the coil is decreasing then the induced emf will try to increase this current or will go in same direction as current is flowing.

In other simple words, Self induce emf will try to oppose in change in current.

This phenomena is known as Self induction.

Formula:-

The formula for self induction could be derive from the formula of induced emf formula.

Where L is the self induction, E is the induced emf and di/dt is the rate of changing current.

From this it is clear that self induction will increase when induced emf will increase and will decrease when rate of changing current will increase.

Unit:- 

Unit of self inductance is Henry(H).

"There will be 1 Henry of self inductance when induced voltage will be one and current will change 1 ampere in one second."

Inductor, Inductance, explanation, formula

Definition:-

"Inductor is an electronic device that is use to store energy in the form of magnetic field."

Explanation:-

Inductor store energy in magnetic field around it. Inductor is an coil of a conductor(wire). wire wounding on some rod or magnet. when a current passes through the conductor then there will be magnetic field around the wire. We wound the wire because by winding there would produce a strong magnetic field around this, we could increase the strength of  magnetic field around coil by taking efficient core like magnet and by increasing number of turns of coil and increasing cross sectional area of inductor. When current flows through the inductor there would produce magnetic field around it and in that magnetic field energy would be store (in the form electrons). It would be store until current is flowing through it. When current will stop it will release all the energy.

Inductor does not allow AC current to flow through it due its changing direction nature. While inductor resist to change in current so it becomes open in a circuit while AC current flows through the circuit. It allows DC current to flow through it. After charging completely it allows DC to flow through the circuit hence become short in circuit with zero resistance.

Inductance:-

Inductance is the property of a inductor which is that "whenever Flux is changed in it, it produces an EMF."

or in simple words

Inductance is the ability of an inductor to store energy in the form magnetic field.

Henry is the unit of Inductance.

Formula:

formula for inductance of inductor is,