Nature of Light: Reflection and Refraction

Nature of Light

• 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.

Characteristics of Light

• 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.

Basic Definitions

Medium

• 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)

Ray

• 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.

Beam

• 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.

Object

• An optical object is defined by incident rays only.
• There are two types of objects:
  • Not specified in the text.

The Town and Its Facilities

• 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.

The Statue of Netaji Subhashchandra Bose

• 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's Features

• 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.