๐ IMPORTANT PHYSICS IN UPCOMING EXAMS (English)
IMPORTANT PHYSICS IN UPCOMING EXAMS (ENGLISH)
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➤ (Alternating Current): An AC current whose magnitude and direction changes with time and after a certain time it repeats in the same direction with the same magnitude, is called alternating current.
➤ Choke Coil: AC coil which allows D.C to pass out inside itself, but creates obstruction in the flow of A.C. is called choke coil.
➤ The choke coil is made by wrapping a coiled copper wire over a core of soft iron.
➤ Due to the choke coil, the value of electrical energy expended in the circuit is minimum.
➤ Choke coil is used in fluorescent tubes and radios of homes.
➤ Transformer: It is a device working on the principle of electromagnetic induction which is used for high A.C. The voltage is reduced to low ac voltage and low ac. High AC to voltage converts to voltage.
➤ Transformer is made by wrapping two coils face to face on a rectangular core of soft iron.
➤ AC The coil connecting to the source is called the primary coil and the coil connecting to the external circuit (load) is called the secondary coil.
➤ Dynamo: It works on the principle of electromagnetic induction.
➤ Dynamo converts mechanical energy into electrical energy.
➤ Electric Motor: It does not work on the principle of electromagnetic induction.
➤ Electrical energy is converted into mechanical energy by electric motor.
➤ Electric Bulb: The electric bulb was first invented by Edison.
➤ Inside the bulb there is a coil-like filament which is made of tungsten metal.
➤ Non-ohmic resistance: Conductors that do not obey Ohm's law are called non-ohmic resistance, such as the resistance of a triode valve.
➤ Electrical conductors and insulating materials: - The materials in which electricity can be easily conducted and electricity flows freely are called insulators and the substances in which the flow of electric current is obstructed are called insulators.
➤ Electrical conductors - copper, silver, graphite, aqueous solutions of salts etc. Insulation - rubber, glass plastic, porcelain etc.
conductors, semiconductors and insulators of electricity
➤ Conductor: In these materials, electric charge flows. Like- silver, copper, aluminum, mercury and other metals water, four coal, human body
➤ Semi-conductor:- The electric charge in these materials is less than that of conductors and more than that of non-conductors. Such as marble, paper, sand, cotton, ivory, moist air etc.
➤ Insulator:- There is no flow of electric charge in these materials. Such as glass, rubber, mica, dry air, silk wood, ebonite, sulphur, lac etc.
➤ Superconductor: A scientist named Ones discovered that at 4.2 K (about -2690C) the electrical resistance of mercury becomes zero. These low temperatures are called critical temperatures and the substances which behave like this are called superconductors.
➤ Superconductors do not present any resistance, so current flows through them without loss of energy.
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