Physics of Light Reflection and Refraction

Reflection of Light

  • Regular Reflection:

    • Occurs on smooth surfaces like mirrors.
    • Parallel rays of light reflected and remain parallel.

  • Diffuse Reflection:

    • Occurs on rough surfaces.
    • Light rays scatter due to uneven surface, making it impossible to see reflections clearly.

SALT Method

  • S: Size

    • Determines if the image is larger, smaller, or the same size as the object.

  • A: Attitude

    • Refers to whether the image is upright or inverted (upside down).

  • L: Location

    • Indicates if the image is in front of, behind, or on the surface of the mirror.

  • T: Type

    • Determines if the image is virtual or real.

Image Formation

  • Image: A) Reproduction of an object created by light.
  • Attitude: The orientation of the image (upright or inverted).
  • Real Image: Formed where light rays converge and can be projected on a screen.
  • Virtual Image: Does not converge on a screen, hence cannot be displayed; appears to be behind the mirror.

Types of Curved Mirrors

  • Converging (Concave) Mirror:

    • Shaped like a portion of a sphere.

  • Diverging (Convex) Mirror:

    • Shaped like the outer surface of a sphere.

Key Components

  • Centre of Curvature:

    • The center point of the sphere that corresponds to the mirror’s curvature.

  • Vertex:

    • Intersection point of the principal axis and the mirror's surface.

  • Principal Axis:

    • Line connecting the center of curvature to the vertex of the mirror.

  • Focus:

    • Point where parallel light rays converge after reflection.

Refraction and Optical Phenomena

  • Refraction:

    • The bending of light as it passes from one medium to another.

  • Optical Illusion:

    • An image that can mislead perception visually.

  • Critical Angle:

    • Angle of incidence at a boundary where refraction occurs. When the angle exceeds this angle, total internal reflection happens.

Lenses

  • Lens:

    • Transparent object that reflects light.

  • Converging Lens:

    • A lens that brings parallel light rays to a single point (focus), thicker at the center than at the edges.