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# What is the use of the chapter magnetic effects of current studied in class 12?

To put it in a nutshell, if one did not study the chapter magnetic effects of current, then one would not have an appreciation for electricity, working of transformers, motors, generators etc. Simply put, you would be one of the many people who only know how to use electricity and electrical appliances without understanding the working principle behind it. read more : marketingproof

When an electric current flow through a conductor, it creates a magnetic field around it. The direction of the magnetic field is dependent on the direction of flow of current by placing the thumb of the right hand, along the direction of flow of current. The direction in which the rest of the fingers curl around the conductor, denotes the magnetic field direction to be wither clockwise or anti clockwise. This is called as the Right-Hand Thumb Rule. On paper, it is visualized by imagining an arrow. If the current is going away from the observer, then one can imagine an arrow moving away. When noticed from this position, the observer can only see the tail of the arrow like a cross. So, to represent the direction of current moving from the observer, a cross X is written on paper and circular lines of magnetic field are drawn around it. The direction of the magnetic field will be clockwise. When the current is moving towards the observer, then an arrow is imagined to be moving towards him and it is represented by a dot with concentric circles around it. The direction of the magnetic field is then anti clockwise in nature. Like electric field, magnetic field is also a vector quantity. It has both direction and magnitude. Magnetic field strength is measured in units of Tesla and is represented by the letter B.

The interaction of electricity, magnetic effect of current and magnetism can be understood by the Faradays Laws of electromagnetism. Faradays Laws can be explained in the following points, that explains the concept of generation of electromotive force (EMF) as experiencing a force. Both the above effects, are utilized in modern science through the application in generators and motors.

• When a conductor is placed in a varying magnetic field, then an electromotive force is developed across the ends of the conductor.
• The magnitude of induced EMF is directly proportional the rate of flux linkage.
• A current carrying conductor when placed in a magnetic field, experiences force on it.

The first law can be understood simply by understanding that for EMF to be induced in any conductor, there must be a relative change in the number of magnetic lines of flux being cut. That means, that there should be a varying flux linkage between the conductor and the magnetic field. This can be accomplished through either changing the strength of the magnetic field continuously (like a sinusoid), or by keeping the magnetic field strength constant and moving the conductor in the magnetic field. In case the conductor circuit is a closed path, then there will be an induction of current in the circuit and this is called as induced current. This is fundamental behind the working of an electric generator.