Theory:

Introduction to light
When we enter a completely dark room, nothing is visible to our eyes, but the moment we switch on the light, everything is visible to us. This is because light can be detected with the help of human eye. It helps us to see things around us. Without light, we cannot see an object.
 
eye light.jpg
  
Sources of light
The objects which can emit light on their own are knowns as luminous objects.
Example:
Sun, torchlight, candle, fireflies, jellyfish, glow-worm.
beach-99388_1280.jpg firefly.jpg candle-1750640_1280.jpg
 
Sun is the major source of natural light. During daytime, light from the Sun falls on the objects (like trees, chair, houses) and helps us to see things around us. Sunlight plays a vital role in the process of photosynthesis. All living things on the earth in way or other depends on sunlight.
 
photosynthesis.jpg
The objects which do not emit light on their own are knowns as non-luminous objects.
Example:
Wood, book, cardboard, paper, etc.
heart-1288420_1280.jpg cardboard-boxes.jpg books-1245690_1280.jpg
Types of objects
Depending on the interaction of light with materials, the objects can be classified into three types.

Transparent objects:
The objects which allow light to pass through them completely are known as transparent objects.
Example:
Eyeglasses, clear drinking glass, clear water, etc.
glasses.jpg drop-of-water-351778_1280.jpg calm-2315559_1280.jpg
  
Translucent objects:
The objects which allow light to pass through them partially are known as translucent objects.
Example:
A rough window glass, butter paper, wax, etc.
white-2563976_1280.jpg wax-paper.jpg
  
Opaque objects:
The objects which do not allow any light to pass through them are called as opaque objects.
Example:
Wall, cardboard, door, stone, etc.
blue-door-2742118_1920.jpg wall-21534_1280.jpg move-2481718_1280.jpg
 
An object can be transparent, translucent or opaque depending on the amount of light passes through it.
Reference:
https://post.greatist.com/wp-content/uploads/sites/3/2020/02/325781_2200-800x1200.jpg
https://media.nationalgeographic.org/assets/photos/119/351/59ca49d4-f7e3-4344-bb90-1597ac521977.jpg
https://i.stack.imgur.com/5RlAz.png
https://3.imimg.com/data3/ET/NA/MY-6294718/wax-paper-500x500.jpg
https://cdn.pixabay.com/photo/2014/08/27/22/36/waterfall-429564_960_720.jpg
https://cdn.pixabay.com/photo/2016/03/27/19/32/blur-1283865_960_720.jpg