TOPIC: LIGHT-REFLECTION
•SUB TOPICS:
SECTION 1- INTRODUCTION TO LIGHT
1. What is light?
2. Characteristics of light
3. Sources of light
4. Medium of light
5. Terms related to light
SECTION 2- REFLECTION OF LIGHT
6. What is the reflection of light?
7. Terms related to reflection
8. Types of reflection
9. Laws of reflection
SECTION 3- PLAIN MIRRORS
10.Reflection by plane mirror
11.Image formed by plane mirror
12.Uses of plain mirrors
SECTION 4- SPHERICAL MIRRORS
13.Spherical mirror and its types
14.Terms related to spherical mirrors
15.Image formation and uses of a concave mirror
16.Image formation and uses of a convex mirror
17.Sign convention for spherical mirrors
18.Mirror formula and magnification
SECTION 1 - INTRODUCTION TO LIGHT
•WHAT IS LIGHT?
● Light is a form of energy that travels in the form of electromagnetic waves and
enables us to see the world around us.
● It moves in straight lines and does not need any material medium to travel.which is
why it can pass through the vacuum of space.
● Light is produced by luminous objects, and when it falls on different surfaces, it can
be reflected, refracted, absorbed, or scattered.
● The behaviour of light helps us understand phenomena like the formation of
shadows, images in mirrors and lenses, and the colours we observe in nature.
● Its speed in vacuum is the fastest known in the universe: about 3 × 10⁸ m/s.
•CHARACTERISTICS OF LIGHT:
1. Light is made up of photons:
● Light consists of tiny packets of energy called photons. Each photon carries energy
that depends on the frequency of the light. The higher the frequency, the greater the
, energy of each photon. This relationship is expressed by the formula E = hF, where E
is energy, F is frequency, and h is Planck’s constant. Photons move at the speed of
light and have no mass, but they still transfer energy when they strike a surface.
2. Light travels in a straight line:
● Light moves in straight paths as long as it travels through a uniform medium. This is
why sharp shadows are formed and why light can be reflected or refracted. The
speed of light is 3 × 10⁸ m/s in vacuum, which is the maximum speed anything can
have in the universe. Light travels slower in materials like water or glass and the
slowest in solids because particles are closer together. Its change in speed while
entering different media is the reason refraction happens.
3. Light shows reflection and refraction:
● When light hits the boundary between two different media, it can bounce back into
the same medium. This bouncing back is called reflection and it follows laws like the
angle of incidence equals the angle of reflection. Light can also bend when it enters a
new medium, a process known as refraction. This bending occurs because the speed
of light changes from one medium to another. Reflection helps us see objects
through mirrors, while refraction is used in lenses, spectacles, cameras, and many
optical instruments.
•SOURCES OF LIGHT:
•Any object which either emits or reflects light is called a source of light. Sources of Light are
divided into 2 types:
1. Luminous source: A luminous source is any object that can produce or give out its
own light. These objects do not need another light to fall on them in order to be seen.
They shine by themselves because of the energy happening inside them.
Eg. Sun, Led bulbs, Burning candles etc.
2. Non-Luminous source: A non-luminous source is any object that cannot produce its
own light. These objects can only be seen when light from a luminous source falls on
them and gets reflected.
Eg. Moon, Humans, Books etc.
•MEDIUM OF LIGHT:
•Space through which light travels is called the medium of light . On the basis of how much
the light passes through a medium it has been divided into 3 types:
1. Transparent medium: A transparent medium is a material through which almost all
the light can pass. Because light moves freely in it, you can clearly see objects on the
other side. There’s no major blocking, scattering, or absorbing of light.
eg. Clean glass, Air, Clean water etc
2. Translucent medium: A translucent medium is a material through which only some
part of the light can pass. Because light does not pass completely, you can see
objects on the other side, but not clearly. They appear blurred or unclear.
eg. Frosted glass, Butter paper, Thin sheet of plastic etc
•SUB TOPICS:
SECTION 1- INTRODUCTION TO LIGHT
1. What is light?
2. Characteristics of light
3. Sources of light
4. Medium of light
5. Terms related to light
SECTION 2- REFLECTION OF LIGHT
6. What is the reflection of light?
7. Terms related to reflection
8. Types of reflection
9. Laws of reflection
SECTION 3- PLAIN MIRRORS
10.Reflection by plane mirror
11.Image formed by plane mirror
12.Uses of plain mirrors
SECTION 4- SPHERICAL MIRRORS
13.Spherical mirror and its types
14.Terms related to spherical mirrors
15.Image formation and uses of a concave mirror
16.Image formation and uses of a convex mirror
17.Sign convention for spherical mirrors
18.Mirror formula and magnification
SECTION 1 - INTRODUCTION TO LIGHT
•WHAT IS LIGHT?
● Light is a form of energy that travels in the form of electromagnetic waves and
enables us to see the world around us.
● It moves in straight lines and does not need any material medium to travel.which is
why it can pass through the vacuum of space.
● Light is produced by luminous objects, and when it falls on different surfaces, it can
be reflected, refracted, absorbed, or scattered.
● The behaviour of light helps us understand phenomena like the formation of
shadows, images in mirrors and lenses, and the colours we observe in nature.
● Its speed in vacuum is the fastest known in the universe: about 3 × 10⁸ m/s.
•CHARACTERISTICS OF LIGHT:
1. Light is made up of photons:
● Light consists of tiny packets of energy called photons. Each photon carries energy
that depends on the frequency of the light. The higher the frequency, the greater the
, energy of each photon. This relationship is expressed by the formula E = hF, where E
is energy, F is frequency, and h is Planck’s constant. Photons move at the speed of
light and have no mass, but they still transfer energy when they strike a surface.
2. Light travels in a straight line:
● Light moves in straight paths as long as it travels through a uniform medium. This is
why sharp shadows are formed and why light can be reflected or refracted. The
speed of light is 3 × 10⁸ m/s in vacuum, which is the maximum speed anything can
have in the universe. Light travels slower in materials like water or glass and the
slowest in solids because particles are closer together. Its change in speed while
entering different media is the reason refraction happens.
3. Light shows reflection and refraction:
● When light hits the boundary between two different media, it can bounce back into
the same medium. This bouncing back is called reflection and it follows laws like the
angle of incidence equals the angle of reflection. Light can also bend when it enters a
new medium, a process known as refraction. This bending occurs because the speed
of light changes from one medium to another. Reflection helps us see objects
through mirrors, while refraction is used in lenses, spectacles, cameras, and many
optical instruments.
•SOURCES OF LIGHT:
•Any object which either emits or reflects light is called a source of light. Sources of Light are
divided into 2 types:
1. Luminous source: A luminous source is any object that can produce or give out its
own light. These objects do not need another light to fall on them in order to be seen.
They shine by themselves because of the energy happening inside them.
Eg. Sun, Led bulbs, Burning candles etc.
2. Non-Luminous source: A non-luminous source is any object that cannot produce its
own light. These objects can only be seen when light from a luminous source falls on
them and gets reflected.
Eg. Moon, Humans, Books etc.
•MEDIUM OF LIGHT:
•Space through which light travels is called the medium of light . On the basis of how much
the light passes through a medium it has been divided into 3 types:
1. Transparent medium: A transparent medium is a material through which almost all
the light can pass. Because light moves freely in it, you can clearly see objects on the
other side. There’s no major blocking, scattering, or absorbing of light.
eg. Clean glass, Air, Clean water etc
2. Translucent medium: A translucent medium is a material through which only some
part of the light can pass. Because light does not pass completely, you can see
objects on the other side, but not clearly. They appear blurred or unclear.
eg. Frosted glass, Butter paper, Thin sheet of plastic etc
