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  Electron emission Introduction The phenomenon of emission of electrons from the surface of a metal is called electron emission. Electron emissions are  of following types : Thermionic emission Photoelectric emission Field emission or Cold cathode emission Secondary emission Thermionic emission It is the phenomenon of emission of electrons from the metal surface when heated  suitably.  The energy required for emission of electrons from the metal surface is being supplied by thermal energy.  The emitted electrons are called thermal electrons or thermions.  The number of thermions emitted depends on the temperature of the metal surface. Photoelectric emission The phenomenon of emission of electrons from the surface of metal when light radiation of suitable frequency falls on it  is called Photoelectric effect.  The energy to the free electrons for their emission is being supplied by light Photons.  The emitted electrons are called photoelectro...

                                                                                                                                                    Dual Nature of Matter and Radiation Introduction The discovery of phenomena like interference, diffraction and polarization established that wave of nature. Maxwell’s equations of electromagnetism and Hertz experiment on production and detection of electromagnetic waves in 1886 strongly supported the concept of wave nature of light . The discovery of cathode rays by William Crookes in 1879, of X-rays by Roentgen in 1895 and of electrons by J.J. Thomson in 1897 were very importan...

Motion Rest  1. A body is said to be at rest if it does not change its position with respect to other body lying in its surrounding wit time.  2. Examples  A book lying on the table is at rest because it does not change its position with respect to table,  A person sitting in a chair is also an example of rest.  3. The absolute rest is not possible because everything in the universe is in motion according to Big Bang Theory.  Example:  A building is at rest with respect to its surrounding but it is in motion along with the earth around the sun. So, absolute rest is not possible. .  Motion  1. A body is said to be in motion if it changes its position with time, with respect to other bodies of the surrounding.  2. Examples  A bus running on the road is in motion because it is changing its position with time , with respect to its surrounding .  A bird flying in air, a train moving on rails, a ship sailing on water, a man walk...

Topics Reference :   PHYSICS CLASS-12 CBSE/JEE/NEET/BSEB(BIHAR BOARD) LECTURE-3 MAGNETIC EFFECT OF CURRENT: BIOT-SAVART LAW OF MAGNETIC FIELD INDUCTION/ STRENGTH / INTENSITY OR MAGNETIC FLUX DENSITY : Biot and Savart law of magnetic field induction at a point due to a current carrying conductor;  Mathematical form of law ;  Vector form of law ;  Integral form of law ;  Direction of magnetic field induction (B) at a point due to a current carrying conductor BY SHIVANAND CHOUDHARY B.D. GURUKUL Rishi Nagar ,Ranibagh ,Delhi -34 GOOGLE PAGE : https://g.page/BDGurukul FACEBOOK PAGE : S N PHYSICS EXPERT Follow Me On : Facebook Instagram Twitter LinkedIn My Youtube Channel : https://www.youtube.com/c/BDGURUKUL

  Topic Reference PHYSICS  CLASS-12  CBSE/ICSE/IB BOARD/BSEB BIHAR/IIT-JEE/NEET UNIT-2 CURRENT ELECTRICITY LECTURE-001 INTRODUCTION TO ELECTRICITY, ELECTROSTATICS, CURRENT ELECTRICITY AND CHARGE  Electricity What is electricity? Definition of electricity in terms of energy Definition of electricity as a branch of Science Branches of electricity Charge Definition of charge Measurement of charge SI Unit of charge Is charge scala or vector ? Origin of charge Cause of charging a body Please show your support  on social media Website: https://www.snphysicsexpert.com Blog: https://snphysicsexpert.blogspot.com Facebook page: https://www.facebook.com/snphysicsexpert Facebook: https://www.facebook.com/shivanand.chaudhary.5 Instagram: https:www.instagram.com/shivanand.chaudhary.5 Twitter: https://www.twitter.com/snchaudhary2014 LinkedIn: https://www.linkedin.com/in/shivanand-chaudhary-7061028b B.D.GURUKUL Google page: https://g.page/BDGurukul Youtube Ch...