Physics Chapter: Light and Waves

Objectives of the Study

• The study aims to examine reflection, refraction, and light dispersion.

What is Light?

• Light is a part of the electromagnetic spectrum visible to the human eye.
• Light travels in straight lines, known as rays. This is called rectilinear propagation.
• A bundle of rays is called a light beam. There are parallel, divergent, and convergent beams.

Luminous and Non-Luminous Objects

• Luminous objects emit light on their own, for example the Sun and a candle flame.
• Non-luminous objects do not emit light, but instead reflect light from luminous sources. Examples are the Moon and Earth.

Pinhole Camera

• A pinhole camera is a simple camera without lenses.
• It uses a small hole to focus light onto a light-sensitive material, creating a real and inverted image.

Types of Waves

• Light waves are transverse waves. In transverse waves, particle oscillation is perpendicular to the direction of energy transfer.
• Sound waves are longitudinal waves. In longitudinal waves, oscillations are parallel to the wave energy transfer direction. Longitudinal waves cannot travel in a vacuum.

Reflection

• Reflection is the bouncing of light rays off a surface.
• Reflection of light allows us to see non-luminous objects.
• The angle of incidence equals the angle of reflection.
• The incident ray, reflected ray, and normal all lie on the same plane.

Reflection for Different Surfaces

• Regular reflection: Occurs on smooth surfaces, creating clear images.
• Diffuse reflection: Occurs on rough surfaces, scattering light and preventing image formation.

Properties of Images Formed by Plane Mirrors

• Images in plane mirrors are the same size as the object.
• Images are upright but laterally inverted (left-right reversal).
• Images are virtual (cannot be projected onto a screen).
• Object distance equals image distance.

Periscope

• A periscope uses mirrors to reflect light, enabling observation from a concealed position.
• Light travel is reflected via multiple reflections.

Refraction

• Refraction is the bending of light as it passes from one transparent medium to another.
• Refraction occurs because light travels at different speeds in different media.
• Denser optical media cause light to slow down.

Daily Phenomena of Refraction

• Swimming pools and ponds appear shallower than they are.
• Objects submerged in water seem to be in a different location.
• Objects in transparent liquids appear to be bent.

Total Internal Reflection

• Total internal reflection is the complete reflection of light within a denser medium when the angle of incidence exceeds a critical angle.

Dispersion

• Dispersion is the separation of light into its component colors.
• White light can be broken up into component colors (ROY G. BIV).
• A prism can be used to split white light.

The Electromagnetic Spectrum

• The electromagnetic spectrum encompasses all forms of electromagnetic radiation, including visible light.

Additive Color Mixing

• Combining red, green, and blue light results in other colors.
• White light comprises all colors of the visible spectrum.
• Combining red, green, and blue light in varying amounts produces a wide array of colors.

Dispersion of Monochromatic Light

• Monochromatic light, containing one color, disperses in a less noticeable manner.
• It doesn't get broken up into different colours when traveling through a prism.