Wave

Light and Optics

Properties of Light

• Light behaves differently in various mediums, such as air, water, and glass.

• The bending of light at the boundary between different media is known as refraction.

Refraction of Light

Pencil in Water

• Observation: A pencil appears bent when partially submerged in water (Figure 10.1).

• Explanation: Light travels at different speeds in air and water, causing the apparent bending of the pencil.

Reflection from Bubbles

• Observation: Air bubbles in water reflect light like a mirror (Figure 10.2).

• Explanation: Light reflects at the interface between water and air instead of passing through.

Magnification with Hand Lens

• Observation: Letters appear larger through a hand lens (Figure 10.3).

• Explanation: The special structure of the glass in lenses causes light to converge, enlarging the image.

Formation of Rainbow

• Observation: A rainbow consists of seven colors formed when sunlight splits while passing through water droplets (Figure 10.4).

• Explanation: Cone cells in the eye allow us to perceive these colors via refraction and dispersion.

Blurred Vision

• Causes: Inability to change lens thickness; loss of transparency in eyes.

• Types of Problems:

  • Difficulty seeing distant or nearby objects clearly.

  • Distinguishing colors.

• Solutions: Eye examinations and prescription spectacles to correct vision.

Speed of Light in Different Media

Classification of Media

• Transparent mediums: air, water, glass, etc.

• Speed of Light (m/s):

  • Air: 3.00 x 10^8

  • Water: 2.25 x 10^8

  • Kerosene Oil: 2.08 x 10^8

  • Glass: 2.00 x 10^8

  • Diamond: 1.24 x 10^8

• Denser Medium: Light travels slower.