light energy definations Flashcards
speed of light in air,water,glass
in air 310 8 m s-1
in water 2.25 * 10 8 ms-1
in glass 2 10 8 m-1
speed of light determine optical density of a medium
by changing the direction of path of light
which is optically denser water or air
water because the speed of light in air is more than the speed of light in water
which is rarer air or glass
speed of light in air is more than the speed of light in glass so air
what is refraction of light
the change in direction of path of light when it passes from a optically transparent medium to another
a ray of light travels from rare medium to denser, how will it bend
towards the normal
’’ ‘’ ‘’ ‘’ ‘’ ‘’ ‘’ ‘’ ‘’ ‘’ ‘’ denser to rarer medium how will it bend
away from the normal
why does a coin placed at the bottom of the vessel appears to be raised when water is poured
due to refraction of light from water to air
what is mirage
an inverted, image of a tree is seen under the water which gives a false impression, it is caused due to refraction of light
what is a prism
a transparent medium bounded by 5 plane surface with a triangular cross section
what is dispersion
a white light is passed through a prism, it splits into different colours
what is spectrum
a band of colours is obtained on the screen the colours are red, orange, yellow, green, blue, indigo, and voilet in order to form the base of the prism upwards after refraction is called a spectrum
2 laws of refraction of light
the angle of incidence should be equal to the angle of refraction
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2 types spherical mirror and distinguish them
the two types of mirror are concave and convex
concave mirror :- made by silvering on the outer part of the spherical mirror so that the refraction takes place from the inner path of the hallow sphere
convex mirror :- made by silvering on the outer part of the mirror so that the refraction takes place from the convexed sphere
what is a pole
geometric center of center of curvature of a mirror is the center of sphere of which mirror is a path and it is represented by symbol C
center of curvature
the center of sphere of which mirror is a part and is represented by symbol C
radius of curvature
the radius of mirror of which mirror is a part and is represented by symbol R
principle axis
straight line joining the pole of the mirror, it may extend on either side of pole
what is the focus and focal length of a spherical mirror
focus is a point on principle axis at which light rays are incident to the principle axis meet after refraction of the mirror
focal length :- the distance from the pole of the mirror to the focus point of the object
how is the focal length of a spherical mirror related of radius of curvature
radius of curvature is observed to be equal to twice of the focal length
what is the real image
formed when reflected ray meet at a point, it is inverted and can be obtained on screen
2 uses of concave mirror
a shaving mirror and reflexcted
2 uses of a convex mirror
a rear view mirror and a reflector in street lamp
a driver uses a convex mirror as a rear view mirror explain
convex mirror diverges the incident ray and forms a small and erect image between pole and focus
