Light - Reflection and Refraction

Question 1

The area of concave mirror that is exposed to incident light is called __________

Answer 1

aperture

Question 2

Principal axis is the line joining the pole and the ____________.

Answer 2

center of curvature

Question 3

The radius of curvature of a plane mirror is ___________.

Answer 3

infinte

Question 4

The distance between the pole and centre of curvature of a spherical mirror is called _________ .

Answer 4

radius of curvature

Question 5

Spherical mirror with a reflecting surface curved ____________ is called a convex mirror.

Answer 5

outwards

Question 6

The point on the principal axis at which parallel rays converge after reflection from a concave mirror is called the ___________.

Answer 6

focal point

Question 7

An image formed when the light rays do not actually pass through the image location, and would not appear on paper or film placed at that location is referred to as a real image.
(true/false)

Answer 7

true

Question 8

Focus is real in the case of a concave mirror.

Answer 8

true

Question 9

Concave spherical mirrors produce images which can be both real and virtual.

Answer 9

true

Question 10

The diameter of the reflecting surface of a spherical mirror is called aperture.

Answer 10

false

Question 11

What is diffraction of light.

Answer 11

If an opaque object on the path of light becomes very small, light has a tendency to bend around it and not walk in a straight line

Question 12

Real image is formed on the ________ side of the mirror .

Answer 12

left side i.e. that is in front of the mirror

Question 13

Virtual image is formed on the ______ side of the mirror

Answer 13

right side i.e. behind the mirror

Question 14

State some uses of CONCAVE MIRROR and their reason

Answer 14

1. torches, search lights, headlights as the bulb is fixed on focus, the reflected rays become parallel and give uniform illumination.
2. Shaving mirrors - to see a larger image of face
3. Dentist - As the mirror is bought close to the teeth i.e. the object is b/w P & F so the image formed id erect, virtual and enlarged
4. Large concave mirror are used to concentrate sunlight to produce heat in solar furnaces

Question 15

A spherical mirror, whose reflecting surface is curved

inwards is called

Answer 15

Concave Mirror

Question 16

A spherical mirror whose reflecting surface is curved

outwards, is called

Answer 16

Convex Mirror

Question 17

What are the uses of Convex mirror ?

Answer 17

1. Convex mirrors are commonly used as rear-view (wing) mirrors in vehicles. These mirrors are fitted on the sides of the vehicle, enabling the driver to see traffic behind them to facilitate safe driving.
2. Also, they have a wider field of view as they are curved outwards. Thus, convex mirrors enable the driver to view much larger area than would be possible with a plane mirror.
3. Convex mirrors are preferred because they always give an erect, though diminished, image.

Question 18

Set of Sign Convention is called the_______________

Answer 18

New Cartesian Sign Convention

Question 19

What is the “Mirror Formula” ?

Answer 19

1/f = 1/u + 1/v

Question 20

What happens when light enters from a denser to rarer medium ?

Answer 20

Light bends away from the normal

Question 21

What happens when light enters from a rarer to denser medium ?

Answer 21

Light bends towards the normal

Question 22

What is the Snell’s law of refraction ?

Answer 22

The ratio of sine of angle of incidence to the sine of angle of refraction is a constant, for the light of a given colour and for the given pair of media.

Question 23

A ray of light through the optical centre of a lens passes w/o suffering any deviation (true /false)

Answer 23

True

Question 24

Centre of an aperture in a lens is called ________ and is denoted by ________

Answer 24

optical centre, O

Question 25

What is the lens formula?

Answer 25

1/v - 1/u = 1/f

Question 26

the degree of convergence or divergence of light rays achieved by a lens is expressed in terms of its _____________

Answer 26

power

Question 27

The power of lens is defined as the reciprocal of ___________

Answer 27

focal length i.e. P = 1/f

Question 28

What is the S.I. unit of Power? and what is it denoted by ?

Answer 28

dioptre and is denoted by 'D'