Class 10 Magnetic Effect of Electric Current
Cbse Class 10 Magnetic Effect of Electric Current
Class 10 Magnetic Effect of Electric Current Notes
Introduction – What is Magnetic Effect of Electric Current
What is the Magnetic Effect of Electric Current – As we have already studied electricity and its effects you will be surprised to know that the magnetic effect and heating effect are after-effects of current?
In this chapter, we are going to focus on the magnetism produced due to electricity and also electricity produced due to magnetism. So let us study about magnets and their properties.
At first, the magnetic concept came in to notice when it was observed that in the center of the earth i.e. the core, there is a substance that can attract certain substances towards itself and that substance is regarded as a natural magnet called a lodestone. Considering the properties of the natural magnet, the man-made magnets were developed. So let us define magnet first.
Magnet: It is an object which attracts pieces of iron, steel, etc. towards itself.
Man made magnets are of different shapes like
Bar magnet- a long rectangular piece of magnet
Horseshoe shaped- U shaped magnet
Magnetic needle
Magnetic compass
Some facts about magnets:-
When a magnet is freely suspended, it always aligns towards north-south direction.
Like poles always repel & opposite poles attract each other.
Magnet always exists as dipole
Two poles can never be separated: if we try to cut them then also, both the poles will exist even in a small piece of magnet. It automatically develops the lost polarity.
A magnet always develops certain area around it where its effect can be felt i.e. magnetic field.
Magnetic field
It is studied by drawing imaginary lines called magnetic lines of forces.
Characteristics of Magnetic Field:
They always originate from north pole & terminate at the south pole. This shows that if the north pole was free, it would have moved towards the south pole.
The place where they are closer indicates a strong magnetic field i.e. at the poles.
Magnetic Field lines give the direction of magnetic force.
Two magnetic lines will never intersect each other as they give direction of force & force can not have 2 directions at a time.
Magnetic Field lines are closed continuous curves.
Magnetic lines produced around bar magnet :
Oersted’s experiment :-
He conducted an experiment and proved that a wire carrying an electric current produces a magnetic field around it. The direction of magnetic field was confirmed by the deflection of magnetic needle kept near the current carrying conductor or we can say near the circuit.
The rules that are given are listed below :
Ampere swimming rule: Suppose a person is swimming in the direction of current such that current enters the man through his feet and leaves his body through his head, then the magnetic needle kept below it will get deflected towards it.
Snow rule: According to this rule, when the current flows from the south to the north, the needle deflects towards the west.
Magnetic field produced by straight conductor
straight conductor
Characteristics
(a) Magnetic lines are concentric circles.
(b) The direction of magnetic lines reverses as we reverse the direction of the current.
When current flows upward, the direction of magnetic lines is anticlockwise.
When current flows downward, the direction of magnetic lines is clockwise.
(c) The Magnetic field produced is directly proportional to the current & inversely proportional to the distance from the conductor.
(d) To know the direction of magnetic field around a straight conductor, we have different sets of rules as given below:
Right hand thumb rule: Suppose you grasp the conductor in your right hand such that the thumb points in the direction of the current, then the direction in which your fingers curl gives the direction of the magnetic field.
Magnetic field produced due to circular loop
The Magnetic field produced around a circular loop is also circular. As we move away from the loop, the concentric circle becomes bigger. At the centre, the magnetic lines are parallel.
Characteristics
The magnetic lines are circular at the points from where the current enters or leaves the coil.
Within the space enclosed by the coil, the field lines are in the same direction.
Near the centre of the coil, the magnetic lines are almost parallel to each other.
At the centre of the coil, the plane of magnetic field lines is at right angles to the plane of circular coil.
Magnetic field produced is directly proportional to the current and inversely proportional to the distance from the conductor.
The part from where the magnetic lines enter the coil facing us is considered as south pole and the other is north pole.
Current flowing clockwise = south
Current flowing anti clockwise = north
