TO - Rectilinear Propagation of Light
Rectilinear Propagation of Light
"In a honogenous and isotropic medium, light travels in a straight line"
Rectilinear Propagation of Light
"Light travels in a stright line as long as it is not reflected, refracted or absorbed."
Pinhole camera
A lensless devicd consists of a light tight box of adjustable length and dark interior
Umbra
A point source blocked by an opaque object will produce a shadow called -
Camera Obscura or Porta's camera
Also known as Pinhole camera (Darkened room/Chamber)
Umbra and Penumbra
An extended source blocked by an opaque object will form a shadow of 2 regions
Total shadow / Absolute shadow / Geometric shadow
Another name for umbra
Shadows
Dark image formed by intercepting light rays
Penumbra
Derived from the word " Paene" which means "nearly"
Umbra
It is the central uniform dark region of the shadow with sharp boarder.
Penumbra
It is the outer annular region of the shadow with partial illumination
Umbra
Latin word which means "Shade"
Eclipse
Natueal phenomenon which further demonstrates the law of Rectilinear propagation of light
Giambattista Della Porta
Perfected the pinhole camera
Partial Illumination
The outer annular region of illumination with darkness
Full illumination
The uniform central region of illumination
Solar and Lunar eclipse
Two types of eclipse
Alhazen
invented the pinhole camera and failed