Nature of Light: Reflection and Refraction

Study Notes

Light travels in a straight line, known as a ray, from the source to the observer.
This rectilinear propagation of light explains everyday experiences of reflection and refraction.

The speed of light in a vacuum or free space is approximately 310,000,000 m/s, slightly lower in air.
The speed of light changes when it travels from one medium to another, with speeds of 2.25 x 10^8 m/s in water and 2 x 10^8 m/s in glass.
Light travels in a straight line, but can be reflected by polished surfaces like mirrors.
The frequency of light remains the same in all mediums.
Light undergoes refraction when it travels from one transparent medium to another.

A medium is a substance through which light propagates or is able to propagate.
There are three types of media:
- Transparent: allows light to pass through easily (e.g., glass, water)
- Translucent: allows light to pass through partially (e.g., oil paper, ground glass)
- Opaque: blocks light from passing through (e.g., wood, iron)

A ray is the straight line path along which light travels in a homogeneous medium.
It is represented by an arrowhead on a straight line, indicating the direction of light propagation.

A beam is a bundle or bunch of rays.
There are three types of beams:
- Convergent beam: diameter of beam decreases in the direction of the ray.
- Divergent beam: diameter of beam increases as the rays proceed forward.
- Parallel beam: all rays move parallel to each other, with a constant beam diameter.

The town is not very big, with only a few pucca houses and a single cottage.
It has a boys' school, a girls' school, a small cement factory, two open-air cinemas, and a municipality.
The municipality is active, undertaking various initiatives like building roads, constructing toilets, and organizing literary events.

A marble statue of Netaji Subhashchandra Bose was installed at the main crossing of the town's main market.
The story revolves around this statue and its smaller part.
The statue was likely created by a local artist, Motilal Ji, the drawing master of the town's only high school, due to the high cost of hiring a renowned artist.
Motilal Ji took a month to complete the statue, which was a bust (from the top of the hat to the second button of the coat) around two feet tall.

The statue was made of marble and depicted Netaji in a military uniform.
It was a beautiful representation of Netaji, with a naive and innocent look.
The statue evoked memories of Netaji's famous phrases like "Delhi Chalo" and "Tum mujhe khoon do".
The only flaw in the statue was the absence of glasses on Netaji's eyes, which was a noticeable omission.