Light, Shadows and Reflections: science class six
Luminous and Non-Luminous Object
There are two types of objects around us. One is called Luminous Object and other is called Non-Luminous Object.
Luminous Object
Objects that emit light are called Luminous Objects .
In the other words objects that produce light are called Luminous Objects.
Example of luminous objects
Sun, Starts, a lighted electric torch, an electric bulb, gas flame, an ignited piece of coal, a lighted candle, a lighted lantern, etc. are some examples of objects that emit light and are known as Luminous Objects.
Since the Sun has its own light, this means the Sun emits light, so it is a Luminous Object.
All stars emits light, so starts are the Luminous Objects.
A torch when put on emits light, so the bulb of a torch is a Luminous Objects.
Similarly, an electric bulb when put on emits light, so an electric bulb is a Luminous Object.
A candle when lighted emits light, and hence a lighted candle is a Luminous Object.
In a similar way, a lighted lantern emits light, and hence a lighted lantern is a Luminous Object.
In ancient times during the night candles, lanterns, etc. are used to light homes. Even today, in many villages candles and lanterns, are used to illuminate homes.
Non-Luminous Object
Objects that do not emit light are called Non-Luminous Objects.
In other words, objects that are not the sources of light either naturally or artificially are known as Non-Luminous Objects.
Example of Non-Luminous Objects
A planet. A planet does not have its own light so a planet is a Non-Luminous Object.
The Moon. Moon does not have its own light so the Moon is a Non-Luminous Object.
A torch in the off position. A torch does not emit light in the off position. So, a torch in the off position is a Non-Luminous Object.
An electric bulb when not getting an electric supply is a Non-Luminous Object. Because in the absence of electricity, a bulb does not produce light.
A tree, an electric pole, water, soil, stone, notebooks, books, a pen, a pencil, an eraser, a table, a chair, a building, etc. are some examples of Non-Luminous Objects..
Thus, all the things which do not emit light are Non-Luminous Objects..
Candle Light Dinner
Even today in the time of modern days candlelight dinner is famous in the cities. In hotels in the cities, all lights are put off and a candle is put on the dining table where the customer is taking dinner or breakfast. In such a case the candle is used as a Luminous Object. Although this, candlelight dinner is arranged by the restaurant owner at the request of the customer.
If the Moon is a Non-Luminous Object, then how do we see it shining in the sky during the night?
Answer
We see the Moon in the sky shining while this is a non-luminous object. The light coming from the sun falls on the Moon and after reflection, it reaches the earth and our eyes, and we can able to see the Moon shining in the sky.
The very big surface of the Moon reflects most of the light coming from the Sun to it which reaches the earth. And in the night because of the absence of the Sun, it appears to produce light and appears as a Luminous Object.
How do we see the planets in the night while planets do not emit light?
Similar to the Moon light coming from the Sun gets reflected from the surface of the planets which reaches earth and consequently to our eyes. This enables us to see stars in the night even if planets do not have their own light.
This is similar to the other non-luminous objects present in our room which can be seen in the presence of light.
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