light energy definations

Question 1

speed of light in air,water,glass

Answer 1

in air 310 8 m s-1
in water 2.25 * 10 8 ms-1
in glass 2 10 8 m-1

Question 2

speed of light determine optical density of a medium

Answer 2

by changing the direction of path of light

Question 3

which is optically denser water or air

Answer 3

water because the speed of light in air is more than the speed of light in water

Question 4

which is rarer air or glass

Answer 4

speed of light in air is more than the speed of light in glass so air

Question 5

what is refraction of light

Answer 5

the change in direction of path of light when it passes from a optically transparent medium to another

Question 5

a ray of light travels from rare medium to denser, how will it bend

Answer 5

towards the normal

Question 6

’’ ‘’ ‘’ ‘’ ‘’ ‘’ ‘’ ‘’ ‘’ ‘’ ‘’ denser to rarer medium how will it bend

Answer 6

away from the normal

Question 7

why does a coin placed at the bottom of the vessel appears to be raised when water is poured

Answer 7

due to refraction of light from water to air

Question 8

what is mirage

Answer 8

an inverted, image of a tree is seen under the water which gives a false impression, it is caused due to refraction of light

Question 9

what is a prism

Answer 9

a transparent medium bounded by 5 plane surface with a triangular cross section

Question 10

what is dispersion

Answer 10

a white light is passed through a prism, it splits into different colours

Question 11

what is spectrum

Answer 11

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

Question 12

2 laws of refraction of light

Answer 12

the angle of incidence should be equal to the angle of refraction

Question 13

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2 types spherical mirror and distinguish them

Answer 13

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

Question 14

what is a pole

Answer 14

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

Question 15

center of curvature

Answer 15

the center of sphere of which mirror is a part and is represented by symbol C

Question 16

radius of curvature

Answer 16

the radius of mirror of which mirror is a part and is represented by symbol R

Question 17

principle axis

Answer 17

straight line joining the pole of the mirror, it may extend on either side of pole

Question 17

what is the focus and focal length of a spherical mirror

Answer 17

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

Question 17

how is the focal length of a spherical mirror related of radius of curvature

Answer 17

radius of curvature is observed to be equal to twice of the focal length

Question 17

what is the real image

Answer 17

formed when reflected ray meet at a point, it is inverted and can be obtained on screen

Question 18

2 uses of concave mirror

Answer 18

a shaving mirror and reflexcted

Question 19

2 uses of a convex mirror

Answer 19

a rear view mirror and a reflector in street lamp

Question 20

a driver uses a convex mirror as a rear view mirror explain

Answer 20

convex mirror diverges the incident ray and forms a small and erect image between pole and focus