LIGHT (exam oriented)

          PHYSICS

Father of physics :- ISSAC NEWTON

    two major book written by Issac newton

1. Principia Mathematica (its about gravity)
2. Optics ( explains about light)

Father of modern physics :- ALBERT EINSTEIN 

LIGHT

• Study of light :- Optics
• Fear to light    :-  photo phobia
• Light has maximum speed in vacuum and least speed in diamond 
• Particle which has greater speed than light :-Taceon ( discovered by ECG sudarsan)
• unit of light is CANDILA
• light year :- it is the time taken for light to travel a year . it is used to measure the distance between stars 
• Distance between planet is measured by astronomic unit (AU); 1AU= 500sec lighttravel =15crkm
• 1Parsec= 3.26 light year > unit to measure distance between galaxy
• Andromeda is the nearest galaxy 

PROPERTIES OF LIGHT 

1.  Scattering :-scattering of light due to the dust particles , waterdrops etc in the medium it travel is known as scattering                                                                                                                        example
1. blue colour of sky --> explained by lord raily
2. blue colour of sea --> explained by cv raman in 1928{ feb 28-- national science day} raman effect
3. tidal effect --> tail of shooting star 
2. Refraction :- bending of light when moving from one medium to another                                 example   
1. mirage 
2. twinkling of star 
3. Total internal reflection :-
1. shining of diamond
2. OFC :- optical fiber cable
4. Diffraction:-example 
1. colour in the cd
5. Dispersion :-dividing of white light to VIBGYOR
1. rain bow 
2. prism colours

GASES USED IN DIFFERENT COLOUR LIGHT

1. WHITE       :-          MERCURY 
2. YELLOW   :-          SODIUM
3. GREEN       :-          CHLORINE
4. BLUE          :-          HYDROGEN
5. ORANGE    :-          NEON
6. PURPLE      :-          ARGON
7. RED             :-          NITROGEN 

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