- 1. Optics: lenses, mirrors, and electromagnetic spectrum
2. Properties of Light
- Light travels in straight lines
- Light travels much faster than sound
- We see things because they reflect light into our eyes
- Shadows are formed when light is blocked by an object
- Luminous and non-luminous objects
Aluminousobject is one that produces light. Anon-luminousobject
is one that reflects light. 4. Visible spectrum 5. Visible Eac h co
lor is a differe nt si ze w ave . Red the longest &violet the
- The sun and other astronomical objects
RoyG.Biv 6. What are sun rays?
- The sun emits several kinds of electromagnetic radiation:
Visible (Vis), Infrared (IR) and Ultra Violet (UV)
- Each kind is distinguished by a characteristic wavelength,
frequency and energy
- Higher energy radiation can damage our skin
High EnergyLow Energy 7. Colour
- White light is not a single colour; it is made up of a mixture
of the seven colours of ther a i n b o w .
We can demonstrate this by splitting white light with a prism:
Angle of incidence = Angle of reflection The same !!! 9. Clear
vs. Diffuse Reflection
- Smooth, shiny surfaces have aclearreflection:
Rough, dull surfaces have adiffuse reflection. Diffuse
reflection is when light is scattered in different directions 10.
- The change in direction of a wave as is crosses the boundary
between two media in which the wave travels at different
11. Convex lenses
- Refracts parallel light rays so they come together at a single
- Distance from center of lens to focal point = focal
- The thicker the middle of the lens the shorter the focal
12. Concave lenses
- Refracts the rays so they come apart.-Known as divergence.
- Always forms a virtual image.
- Show overhead ofconcave lens .