Information about 12th Standard School Subject content with Free PDF (Physics, Chemistry and Biology) for Preparation of NEET Examination, IIT-JEE Examinations and other entrance examinations in India. Study materials contain NCERT, CBSE, ICSE.
ELECTROMAGNETIC WAVES – James Clerk Maxwell, DISPLACEMENT CURRENT, ELECTROMAGNETIC WAVES, Sources of electromagnetic waves, Nature of electromagnetic waves, Heinrich Rudolf Hertz (1857 – 1894), Microwaves and Microwave oven (NCERT 12TH PHYSICS) An electric current produces magnetic field and that two current-carrying wires exert a magnetic force on each other. A magnetic field changing with time …
ALTERNATING CURRENT – Nicola Tesla, George Westinghouse and Resonance (NCERT 12TH PHYSICS) We have so far considered direct current (dc) sources and circuits with dc sources. These currents do not change direction with time. But voltages and currents that vary with time are very common. The electric mains supply in our homes and offices is …
ELECTROMAGNETIC INDUCTION – Joseph Henry, Michael Faraday, The Experiments of Faraday and Henry, MAGNETIC FLUX, FARADAY’S LAW OF INDUCTION, LENZ’S LAW AND CONSERVATION OF ENERGY, EDDY CURRENTS, ELECTROMAGNETIC DUMPING, INDUCTANCE, Self-inductance and AC GENERATOR (NCERT 12TH PHYSICS) Electricity and magnetism were considered separate and unrelated phenomena for a long time. In the early decades of …
MAGNETISM – Diamagnetism, Paramagnetism, Ferromagnetism and PERMANENT MAG NETS AND ELECTROMAGNETS (NCERT 12TH PHYSICS) Diamagnetism Diamagnetic substances are those which have tendency to move from stronger to the weaker part of the external magnetic field. In other words, unlike the way a magnet attracts metals like iron, it would repel a diamagnetic substance. A bar …
EARTH MAGNETISM – Magnetic declination and dip, Compass at the pole and Earth’s Magnetic Field (NCERT 12TH PHYSICS) THE EARTH’S MAGNETISM Earlier we have referred to the magnetic field of the earth. The strength of the earth’s magnetic field varies from place to place on the earth’s surface; its value being of the order of …
MAGNETISM AND MATTER – The Bar Magnet and Magnetic Field lines (NCERT 12TH PHYSICS) Magnetic phenomena are universal in nature. Vast, distant galaxies, the tiny invisible atoms, humans and beasts all are permeated through and through with a host of magnetic fields from a variety of sources. The earth’s magnetism predates human evolution. The word …
PHYSICAL SIGNIFICANCE OF ELECTRIC FIELD (NCERT 12 PHYSICS PART 1) You may wonder why the notion of electric field has been introduced here at all. After all, for any system of charges, the measurable quantity is the force on a charge which can be directly determined using Coulomb’s law and the superposition principle [Eq. (1.5)]. …
ELECTRIC FIELD (NCERT 12TH PHYSICS PART 1) Let us consider a point charge Q placed in vacuum, at the origin O. If we place another point charge q at a point P, where OP = r, then the charge Q will exert a force on q as per Coulomb’s law. We may ask the question: …
ELECTRIC CHARGE AND FIELDS – CONDUCTORS AND INSULATORS, CHARGING BY INDUCTION AND BASIC PROPERTIES OF ELECTRIC CHARGE (NCERT 12TH PHYSICS PART 1) CONDUCTORS AND INSULATORS A metal rod held in hand and rubbed with wool will not show any sign of being charged. However, if a metal rod with a wooden or plastic handle is …
ELECTRIC FIELD AND CHARGES ELECTRIC FIELD AND CHARGES – INTRODUCTION (Electric Charge – NCERT 12TH PHYSICS) INTRODUCTION All of us have the experience of seeing a spark or hearing a crackle when we take off our synthetic clothes or sweater, particularly in dry weather. This is almost inevitable with ladies garments like a polyester saree. …