describe light shadow and reflection full chapter and follow me
Answers
Luminous Object: An object which produces light is called a luminous object, e.g. sun, bulb, etc.
Non-luminous object: An object which does not produce light is called non-luminous object, e.g. moon.
Light always travels in a straight line. This can be proved by a simple experiment. For this, take a cylindrical tube; which can be easily bent. Try to see a source of light; like a bulb or a candle; through the straight tube. Once the tube is bent at some angle, it is not possible to see the source of light through it. This happens because light travels in a straight line.
Transparent Object: An object which allows complete passage to light is called a transparent object. We can clearly see through a transparent object.
Translucent Object: An object which allows partial passage to light is called a translucent object. We can see through a translucent object but the vision would be faint.
Opaque Object: An object which does not allows passage to light is called an opaque object. We cannot see through an opaque object.

Fig: Transparent translucent
Formation of Shadow
When light falls on an opaque object, a dark patch is formed on the other side of the object; if a screen is present on the other side. Three things are required for formation of shadow, viz. a source of light, an object and a screen.
The size of shadow depends on the distance of source of light and on the angle at which the light rays fall on the object.
If the source of light is closer to the object, a larger shadow is formed than when the source of light is far from the object.
If the angle of incident light is smaller, the shadow is longer. On the other hand, if the angle of incident light is bigger, the shadow is smaller. This explains, why our shadows are longer in the morning and evening and smaller in the noon.
Structure of a pinhole camera:

Fig: Pinhole camera
A pinhole camera is simple device. One can get an inverted and real image in a pinhole camera.
A pinhole camera is composed of two boxes. One of the boxes snugly fits inside another box and can be slid to and fro. There is a pin-sized hole at the front of the camera and a translucent screen at the back of the camera. The distance between the pin-hole and screen can be adjusted to obtain a clear image of an object.
Mirror and Reflection:

Fig: Reflection of Light
When light falls on a shiny surface, the light rays bounce back. This phenomenon is called reflection of light. Mirror is a surface from which most of the incident light
Air, water, a piece of rock, a sheet of aluminium, a wooden board, a sheet of polythene, a sheet of cellophane, a CD, smoke, a sheet of plane glass, fog, a piece of red hot iron, an umbrella, a lighted fluorescent tube, a wall the fame of a gas burner, a sheet of cardboard, a lighted torch, a wire mesh, a mirror, kerosene stove, sun, firefly, moon, a sheet of carbon paper.
Ans:
Object Opaque/Transparent/Translucent Luminous/Non Luminous
Moon Opaque Non-Luminous
Firefly Opaque Luminous
Sun Opaque Luminous
Kerosene Stove Opaque Luminous
A wire mesh – Non-Luminous
A sheet of cellophane Transparent Non-Luminous
A lighted torch Opaque Luminous
A sheet of cardboard Opaque Non-Luminous
The flame of a gas burner Opaque Luminous
A sheet of carbon paper Opaque Non-Luminous
A wall Opaque Non-Luminous
A lighted fluorescent tube Opaque Luminous
An umbrella Opaque Non-Luminous
A piece of red hot iron Opaque Luminous
A sheet of plane glass Transparent Non-Luminous
Fog Translucent Non-Luminous
Smoke Translucent Non-Luminous
A CD Opaque Non-Luminous
A sheet of polythene Translucent Non-Luminous
A wooden Board Opaque Non-Luminous
A mirror Opaque Non-Luminous
A sheet of aluminium Opaque Non-Luminous
A piece if rock Opaque Non-Luminous
Water Transparent Non-Luminous
Air Transparent Non-Luminous
Q2. How would you create a circular shadow if held in one way and a rectangular shape shadow held in another way, with the object?
Ans: Yes, there are many objects like a cylinder and a circular disc, which would give a circular shadow if held in one way and a rectangular shadow if held in another way.
(a) Circular shadow with cylinder
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(b) Rectangular shadow with cylinder
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Q3. In a completely dark room, if you hold up a mirror in front of you, will you see a reflection of yourself in the mirror?
Ans: No, in a completely dark room, there won’t be any light in the room, so there won’t be any reflection of light and no image will be formed on the mirror.
VERY SHORT ANSWER TYPE QUESTIONS
Q1. Is the moon luminous or non-luminous body?
Ans: Moon is a non-luminous body.
Q2. What is umbra?
Ans: The dark shadow region which falls behind the object where no light enters is called Umbra.
Q3. How does light ray travel?
Ans: Light ray travels in a straight line.
Q4. Give one natural source of light.
Ans: Sun and stars are some of the natural sources of light.
Q5. What is a shadow?
Ans: Shadow is the dark area behind any opaque object where the light cannot pass through.
Q6. What is penumbra?
Ans: The partially shaded region which is less darker than the umbra, behind any opaque object is known as Penumbra.
SHORT ANSWER TYPE QUESTIONS
Q1. What is the difference between a luminous and a non-luminous body?
Ans: The bodies which have its own source of