INTRODUCTION
OF LIGHT
What is light ? What is light in physics?
What is meant by light? Define light.
Ans: Light enables us to see several thousands of objects every day. Though light is invisible, it makes objects around us visible. The primary source of light is the Sun. Other sources of light are an incandescent bulb, a fluorescent bulb, LET (Light Emitting Diode) the stars, etc. In an incandescent bulb, the filament is heated to a high temperature, and thus, the heat energy is converted into light.
Ø Light is an electromagnetic radiation and can travel through vacuum. Thus, light is a form of energy which enables vision.
What are luminous bodies and non- luminous bodies? Define luminous bodies and non-luminous bodies?
Ans:
luminous bodies:
The bodies which give light on their own are called luminous bodies. Example, the Sun, the stars, a glow worm, an electric bulb, a candle, etc.
non-luminous bodies
The bodies which do not give out light on their own but are
made visible due to the reflection of light are called non-luminous bodies.
Example: chairs, walls, the moon, etc.,
What is optical medium ? What is optical medium n physics?
Define optical medium and its types?
The medium through which light passes is called an optical
medium. Optical media are further classified into homogenous and
heterogenous.
What is Homogenous Media and Heterogenous Media ?
1- Homogenous Media:
An optical medium like pure water or glass have uniform composition
In a homogenous medium, light travels along a straight line.
The straight-line path of light is called ray.
The arrow mark gives the direction in which the light ray
travels.
A bundle of light rays is called beam of light. If the light
rays in a beam of light travel parallel to each other, the beam of light is
called parallel beam.
2- Heterogenous Media: Optical media like air or muddy water, which have different composition.
What is Transparent Media ? What is Translucent Media ?
What is Opaque Media ?
Define Transparent, Translucent and Opaque Media ?
What is Transparent Media ?
Transparent Media:
Media like glass, water, etc., which allow most of the light to pass
through them.
What is Translucent Media ?
Translucent Media : Tissue paper or fog allows only a
part of the light energy to pass through it.
What is Opaque Media ?
Opaque Media: Substances like iron plates, stones,
bricks, etc., do not allow light to pass through them.
