Question

What is light beam? How many types of it are there?

Hint:

Remember: Lasers produce a highly parallel (collimated) beam, while a torch produces a divergent beam. Lenses are used to convert one form of beam into another.

Answer 1

Step 1: Definition of Light Beam
A light beam is defined as a collection or bundle of light rays that travel in the same region of space. Unlike a single ray, which is only an idealized line showing the direction of light, a beam is a practical and visible stream of light that we observe in daily life. For example, when sunlight enters a dark room through a small hole, we can see a clear beam of light with dust particles floating in it.
Step 2: Physical Explanation
Light beams are formed because light rays emerging from the same source usually travel together. Their paths may either be straight, converging at a point, or diverging from a point. This allows us to classify beams into categories.
Step 3: Types of Light Beams
Parallel Beam: All rays are parallel to each other. Such beams do not meet and remain equidistant. Example: Rays coming from the Sun are nearly parallel when they reach Earth.
Convergent Beam: The rays move closer and meet at a single point. Example: A convex lens focusing sunlight on paper produces a convergent beam.
Divergent Beam: The rays spread outward from a point. Example: A torch, bulb, or the headlight of a car produces a divergent beam.
Step 4: Real-Life Importance
Beams of light are important in optics for designing instruments like projectors, microscopes, telescopes, and even in lasers where a very fine parallel beam is produced for medical and industrial applications.
Final Answer:
A light beam is a group of light rays, and it can be of three types: parallel, convergent, or divergent.