Class 12 Physics Chapter 19 Notes

• Important Class 12 Physics chapter 19 mcqs for Intermediate part-II students.
• Relative motion
• Frames of a reference
• The special theory of relativity
• Important Class 12 Physics chapter 19 exercise questions for Intermediate part-II students.
• Time deletion, length contraction, mass variation, energy-mass relation
• NAVSTAR navigation system
• Black body radiation, Intensity distribution diagram plans assumption the phone Photon
• Important Class 12 Physics chapter 19 numericals for Intermediate part-II students.
• Interaction of electromagnetic radiation with matters
• (i) Photoelectric effect  (ii) Compton effect  (iii) Pair production
• Important Class 12 Physics chapter 19 Important numericals for Intermediate part-II students.
• Explanation on the basis of Quantum theory
• Photocell
• Annihilation of matter 
• Wave nature of particle
• Important chapter 19 physics class 12 short questions for Intermediate part-II students.
• Davisson and Germer experiment
• Wave-Particle duality
• Uses of wave nature of particles
• Electron microscope
• Important Class 12 Physics chapter 19 notes handwritten for Intermediate part-II students.
• Uncertainty Principle
• FRAMES OF REFERENCE: We have discussed the most commonly used Cartesian coordinate system In effect, a frame of reference is any coordinate system relative to which measurements are taken. The position of a table in a room can be located relative to the walls of the room. The room is then the frame of reference. For measurements taken in the college laboratory, the laboratory is the reference frame. If the same experiment is performed in a moving train, the train becomes a frame of reference. The position of a spaceship can be describe relative to the positions of the distant stars. A coordinate system based on these stars is then the frame of reference.
• Important 12 class physics chapter 19 exercise for Intermediate part-II students.
• An inertial frame of reference is defined as a coordinate system in which the law of inertia is valid. That is. a body at rest remains at rest unless an unbalanced force produces acceleration in it. Other laws of nature also apply in such a system. If we place a body upon Earth it remains at rest unless an unbalanced force is applied upon it. This observation shows that Earth may be considered as an inertial frame of reference. A body placed in a car moving with a uniform velocity with respect to Earth also remains at rest, so that car is also an inertial frame of reference. Thus any frame of reference which is moving with uniform velocity relative to an inertial frame is also an inertial frame.
• Important ch 2 physics class 19 Notes for Intermediate part-II students.
• When the moving car is suddenly stopped, the body placed in it. no longer remains at rest. So is the case when the car is suddenly accelerated. In such a situation, the car is not an inertial frame of reference. Thus an accelerated frame is a non-inertial frame of reference. Earth is rotating and revolving and hence strictly speaking, the Earth is not an inertial frame. But it can often be treated as an inertial frame without serious error because of very small acceleration.
• Important ch 2 physics class 19 solutions for Intermediate part-II students.
• Special theory of relativity: The theory of relativity is concerned with the way in which observers who are in a state of relative motion describe physical phenomena. The special theory of relativity treats problems involving inertial or non-accelerating frames of reference. There is another theory called general theory of relativity which treats problems involving frames of reference accelerating with respect to one another. The special theory of relativity is based upon two postulates, which can be stated as follows:
• Important ch 2 physics class 19 Important solutions for Intermediate part-II students.
• 1. The laws of physics are the same in all inertial frames. 2. The speed of light in free space has the same value for all observers, regardless of their state of motion.
• Important ch 2 physics class 19 for Intermediate part-II students.
• Length contraction: The distance from Earth to a star measured by an observer in a moving spaceship would seem smaller than the distance measured by an observer on Earth. That is if you are in motion relative to two points that are a fixed distance apart, the distance between the two points appears shorter than if you were at rest relative to them. This effect is known as length contraction. The length contraction happens only along the direction of motion.