T.O - Rectilinear Propagation of Light (prelims)
1. Full Illumination 2. Partial Illumination
2 Regions of illumination is formed if a beam of light coming from an EXTENDED source enters an aperture
1. Lunar Eclipse 2. Solar Eclipse
2 Types of Eclipse
1. Umbra 2. Penumbra
2 regions formed when Extended source is blocked by opaque object
Eclipse
A natural phenomenon which further demonstrates the Law of Rectilinear Propagation of Light
Umbra, total / absolute /geometric shadow
A point source blocked by an opaque object will produce a shadow known as ______, _____/_____, ______
Region of Illumination
Allowing light from a POINT source to ENTER an aperture will cast an image on the second screen
Similat triangles
Are pair of triangles which share a common APEX, wherein one triangle is photographic enlargement of the other
Similar triangles
Are used to solve problems involving rectilinear propagation of light
Partial illumination
Counterpart of Penumbra
Full illumination
Counterpart of Umbra
Shadows
Dark image formed by intercepting light rays
Penumbra
Derived from latin word "paene" which means nearly
A/b = a`/b`
Formula for Ratio and Proportion
Altitude
Height of the triangle
Smaller
If the OBJECT is moved closer to the screen, the shadow gets smaller
Bigger
If the SOURCE is moved closer, the shadow gets _____
Homogeneous and isotropic
In a _____ and ______ medium, light travels in straight line
Umbra
Latin word which means "shade"
Umbra
Light coming from POINT SOURCE will only form _____
Reflected, refracted or absorbed
Light travels in straight line as long as it is NOT _____, ______, or ______
Homogenous medium
Medium with same temperature, refracting index Ex. Air
Penumbra
Outer annular region of the shadow with partial illumination
Lunar Eclipse
Sun - earth - moon
Solar eclipse
Sun - moon - earth
Umbra
The central uniform dark region of the shadow with sharp border
Partial Illumination
The outer annular region of illumination with partial darkness
Full Illumination
The uniform central region of illumination
