How are objects classified based on their interaction with light?
Types of ObjectsMeaningExamples
|
Transparent objects |
Allow the light to pass through them completely. |
Clean air, clear water, etc. |
| Translucent objects | Allow the light to pass through them partially. | Butter paper, plastic sheets, etc. |
| Opaque objects | Do not allow the light to pass through them. | Human body, brick, book, etc. |
What are Shadows?
In the figure, behind the human body, we observe that a dark figure or area is formed. This dark area which forms behind the opaque object (human body in this case) when light is obstructed by it, is called a Shadow.
What are the things required to form a shadow?
- Source of light – To emit light (The light bulb in the above case)
- Opaque object – To obstruct the light (The human body)
- Screen or surface behind the object – For a shadow to be formed on it (The floor)
What are the characteristics of a shadow?
- It is always black, regardless of the colour of the object used to make
- It only shows the shape and outline of the object and not the
- Its size depends on the ‘distance between the source & the object’ and ‘the distance between object & the screen’.
How are shadows formed?
We know one of the reasons! Opaque bodies do not allow light to pass through them. Another important reason for shadows to form is that light travels in a straight line. But we will deal with the second reason in the next segment.