The document discusses the nature and properties of light. It covers early theories on light as particles (Newton) and waves (Huygens). Maxwell's electromagnetic theory unified electricity, magnetism and light. The electromagnetic spectrum is introduced. Common light sources include the sun and artificial lamps. Materials can transmit, scatter, or absorb light depending on whether they are transparent, translucent, or opaque. Light interacts with materials through reflection, absorption, refraction, polarization and scattering. Key characteristics of light discussed are brightness, which depends on source and distance, and luminous intensity measured in candelas.

1. LIGHT

2. NATURE OF LIGHT
Sir Isaac Newton believed that light behaves like a
particle.
Corpuscular or Particle Theory
“Light consisted of streams of particles emitted by the
light source.”
Christian Huygens believed that light behaves like a
wave.
Wave Theory
“Light is a wave that originates from a vibrating
body.”

3. NATURE OF LIGHT
Thomas Young showed that light behaves
like a wave.
Max Planck came up with what is now
known as the Dual-Nature of Light.
James Clark Maxwell proposed the
electromagnetic Theory of Light.

4. Electromagnetic Theory
James Clark Maxwell showed that
electric and magnetic fields were
propagated together and that their
speed was identical with the speed of
light.

5. Electromagnetic Spectrum

6. COMMON SOURCES OF LIGHT
Natural Sources
Luminous body – an object capable of
producing its own light.
Ex: Sun
Artificial Sources
Ex. Lamps, bulbs etc..

7. LIGHT AND MATERIALS
How light behaves when it strikes an
object depends on many factors,
including the material of the object is
made of.
Materials can be:
1. Transparent
2. Translucent
3. Opaque

8. TYPES OF MATERIAL
1. TRANSPARENT
-Transmits light, which means it allows most
of the light that strikes it to pass through it.
2. TRANSLUCENT
-scatter light.
3. OPAQUE
-either absorbed or reflects all the light that
strikes it.

9. TYPES OF MATERIAL

10. INTERACTION OF LIGHT
When light strikes a new medium,
the light can be reflected, absorbed, or
transmitted. When the light is
transmitted, it can be refracted.
Polarized, or scattered.

11. CHARACTERISTICS OF LIGHT
1. BRIGHTNESS
- depends on the source and distance from
the source.
- Can be expressed as luminous intensity
with a unit known as candela.
Photometer- instrument that can measure the
luminous intensity of light.
Luminous Intensity – refers to the amount of
light power emanating from a point source
within a solid angle of one steradian.

12. Assignment:
BRING THE FOLLOWING: (BY
GROUP)
- 1/8 Illustration board
- Plastic filters (Green, blue, and red)
- 3 pieces of high intensity flashlights
- Scotch tape