WELCOME
SREE NARAYANA TRAINING COLLEGE POOCHAKKALB.Ed 2013-2014
SUBMITTED BY
NAME : DEEPA KRISHNAN OPTION SUBJECT : PHYSICAL SCIENCE REG.NO : 13383010
SUBMITTED TO
MRS.LINIMOL K.S LECTURER (PHYSICAL SCIENCE)
POWERPOINT PRESENTATION ON
LIGHT AND SOME RELATED PHENOMENON
REFRACTION
When a ray of light travels from a medium to another having a change in optical density the direction of the wave slightly changes. This is known as REFRACTION
When the incident ray travels from a less optically dense medium (low n) to a more optically dense medium (high n) then the refracted ray bends towards the normal.
LAWS OF REFRACTION
AirGlass
Normal
Higher speed (lower index of refraction)
Lower speed (higher index of refraction)
θi
θr
Refracted ray bends away from the normal
LAWS OF REFRACTION
AirGlass
Higher speed (lower index of refraction)
Lower speed (higher index of refraction)
Refracted ray bends towards the normal
θi
Normal
θr
The apparent depth is less than the real depth because rays of light are refracted from the normal as they leave the water.
The light rays appear to come from a point I which is a virtual image.
Real depth and Apparent depth
Apparent Depth
Objects under water always appear to be nearer to the surface than they actually are
An optical illusion is formed!
TOTAL INTERNAL REFLECTION
If the angle of incidence of a ray is greater than a certain critical angle the ray will reflect rather than reflect This principal is responsible for the properties of fiber optic cables.
TOTAL INTERNAL RFLECTION
MIRAGE AN EXAMPLE FOR TOTAL INTERNAL REFLECTION
REFLECTION
•Diffuse reflection (rough)
reflects light in many different directions,
•Specular reflection (smooth)
reflects light in only one direction
Smooth – variations in surface
TYPES OF REFLECTION
DISPERSION The separation of light into colors arranged
according to their frequency, by interaction with a prism or diffraction grating.
RAINBOWS White light separates into different colors
(wavelengths) on entering the raindrop because red light is refracted by a lesser angle than blue light. On leaving the raindrop, the red rays have turned through a smaller angle than the blue rays, producing a rainbow.
THANK YOU
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