The particles which are structureless, invisible and not regarded as made up of some other particles are called elementary particles. Hundreds of the elementary particles are discovered so far. These particles are fundamental in the sense that these particles can…
Magnetic Hysteresis
Let us consider a ferromagnetic material which is subjected to magnetizing field (H). The intensity of the magnetizing field (H) is gradually increased from 0. Then, the magnetic induction (B) also increases and becomes maximum (at point L in the…
Elements of Earth’s Magnetic Field
The magnetic field of the earth at any point on its surface is determined by using three physical quantities which are called elements of earth’s magnetic field. They are: Declination: Declination at a point of earth’s surface can be defined…
Ampere’s Circuital Law
Ampere’s circuital law was discovered by André-Marie Ampere in the year 1826 A.D. This law states that, “The line integral of magnetic field B along any closed path in free space is equal to the vacuum permeability (μo) times the…
Motion of An Electron in Electric Field
Let us consider that, an electron of mass ‘m’ moves with initial horizontal velocity ‘vx‘. While the electron enters the electric field between the parallel plates, it is attracted towards the upper positive plate. The electrostatic force with which electron…
Hall Effect
When magnetic field is applied perpendicular to a current carrying conductor, then voltage is developed across the conductor in the direction perpendicular to both current and magnetic field. This effect is called Hall effect. Let us consider a rectangular cross…
Moving Coil Galvanometer
Moving coil galvanometer is a device which is used to detect and measure small electric currents present in an electric circuit. Principle It is based on the principle that, “When a current carrying coil is placed in magnetic field, it…
Derivation of Expression for Torque on a Rectangular Coil
Let us consider a rectangular coil PQRS of length ‘l’ and breadth ‘b’ suspended in uniform horizontal magnetic field ‘B’. Let the plane of the coil make an angle ‘θ’ with the direction of magnetic field. When current ‘I’ is…
The First Law of Thermodynamics
We know that heat is a form of energy which flows from a hotter body to a colder body. It is the energy produced due to the total kinetic energy produced by the vibrating molecules of a body. We can…
Friction: A Type of Force
There are different types of force which are used by living beings in their day to day life. Force can be simply defined as the external agency that changes or tends to change the state of a body from rest…