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# Class 9 FRANK Solutions Physics Chapter 6 - Light - Reflection of Light

Understand syllabus concepts easily with the support of Frank Solutions for ICSE Class 9 Physics Chapter 6 Light - Reflection of Light. Go through the points that distinguish divergent beam of light and convergent beam of light. Relearn the concept of rectilinear propagation of light. Also, revise the laws of reflection by utilising TopperLearning’s well-written textbook solutions.

Some of the other topics that you can revise through ICSE Class 9 Frank Solutions include lateral inversion, plane mirror, etc. In addition, learn to draw the correct diagram to show reflected and incident rays as per the given information in a Physics question.

## Light - Reflection of Light Exercise 245

### Solution 1

Light may be defined as the radiant energy which produces in us the sensation of sight. Light itself is invisible but makes other objects visible.

### Solution 2

Yes, light is a form of energy that produces the sensation of vision in our eyes.

### Solution 3

The velocity of light in vacuum is 3 x 108 m/s.

### Solution 4

Two sources of light are
(a). Natural, for e.g. Sun
(b). Artificial, for e.g. Light bulb.

### Solution 5

Four characteristics of light are :-
(a). Light waves can travel through vacuum
(b). Light waves are transverse waves
(c). Wavelength of light waves is short so that their length is measured in centi-microns.
(d). The velocity of light in vacuum is 3 x 108 m/s.

### Solution 6

The Sun and the stars are the two luminous bodies.

### Solution 7

Two non -luminous bodies are moon, chair.

### Solution 9

A ray of light is the path along which light travels.

### Solution 10

Three distinctions between light and sound waves are
(a). Light waves can travel through vacuum while sound waves cannot.
(b). Light waves are transverse waves while sound waves are longitudinal waves.
(c). The velocity of light in air is 3 x 108 m/s while the speed of light in air is just about 330 m/s.

## Light - Reflection of Light Exercise 246

### Solution 11

(a). A ray of light
(b). Divergent beam of light
(c). Divergent beam of light
(d). Parallel beam of light

### Solution 12

The substance through which light is made to pass is called medium.

### Solution 13

Rectilinear propagation of light is that the light travels along a straight line.

### Solution 14

No, glass is a transparent medium.

### Solution 15

No, no metal is transparent by nature.

### Solution 17

Waxed paper is the translucent medium among the given substances.

### Solution 19

Two observations that proves that light travels in a straight line are :-
(a). Sunlight coming through a hole in a dark room, we can easily see that light travels in a straight line
(b). Light coming from a laser light, used for presentation, can also be seen to travel in straight line.

### Solution 20

When rays of light fall on a surface, they are turned back into the same medium in accordance with some definite laws. This process is known as reflection.

### Solution 21

A smooth and polished flat surface is the cause of regular surface.

### Solution 22

Reflection obeys following two laws
(a). The incident ray, the reflected ray, and the normal at the point of incidence, all lie in the same plane.
(b). The angle of incidence and the angle of reflection are always equal.

### Solution 23

The height of plane mirror should be half of the size of the object to get a full image of the object. So for a man of height 1.6 m tall should use a 0.8m tall plane mirror.

### Solution 24

Rectilinear propagation of light is that the light travels along a straight line.

### Solution 25

Lateral inversion is the reversal of image experienced in a plane mirror. The image is of the same size and equidistant from the object but the left and right sides are transposed.

### Solution 26

Formation of image is the phenomenon based on laws of reflection.

### Solution 27

The principle employed in a periscope is successive reflections from two plane mirrors.

### Solution 28

The point at which the light is incident on the reflecting surface is called the point of incidence.

### Solution 29

Any smooth, highly polished reflecting surface is called mirror.

### Solution 30

A smooth, highly polished plane surface is called plane mirror.

### Solution 31

The angle between the incident ray and the normal to the surface at the point of incidence is called the angle of incidence.

### Solution 33

Given, angle between incident ray and mirror = 35o
(a). Angle of incidence = angle of mirror to the normal - angle between incident ray and mirror
= 90 - 35 = 55o
(b). Angle of reflection = angle of incidence = 55o
(c). Total angle turned = angle of incidence + angle of reflection
= 55 + 55 = 110o
(d). The angle between incident ray and reflected ray = Angle of incidence + Angle of reflection = 55 + 55 = 110o

### Solution 34

Given, distance of boy from the mirror = 3 m
(a). Distance of image from mirror = distance of boy from the mirror = 3 m
Distance between boy and his image = distance of boy from the mirror + distance of image from mirror = 3+3 = 6 m
(b). Now, distance of boy from the mirror = 4 m
Distance of image from mirror = 4 m
Distance between boy and his image = distance of boy from the mirror + distance of image from mirror = 4+4 = 8 m.

## Light - Reflection of Light Exercise 247

### Solution 36

Two characteristics of image formed by plane mirror are
(a). Image is erect and virtual
(b). Image and object are of same size.