Light & Optical Instruments Flashcards
How is light produced?
A chemical reaction or it comes naturally for example from the sun.
Define light.
Form of energy that we can see.
Name some natural and artificial sources of light
Natural sources.
Sun stars and fire.
Artificial sources.
Lightbulbs flashlights etc.
Why are fluorescent tubes more energy efficient than incandescent bulbs ?
Fluorescent tubes don’t create thermal energy and you can touch them when they’re lit so therefore it saves more energy
How does light travel?
Light travels in a straight line/path
Describe what happens to light when it strikes different surfaces.
When light hits an opaque surface it cannot travel through. When it hits a translucent surface after passes through, afterwards it goes into other directions but when it hits a transparent surface it goes straight through without changing direction.
Give some examples of a luminous object.
Lightbulb, Candle flame, Christmas lights, certain animals (example some jellyfish and fireflies).
List some nonluminous objects.
Door frame, glass, paper etc.
State the laws of reflection
- the angle of reflection (r) is equal to the angle of incidence (i)
- the incident ray the normal and the reflected ray are always in the same plane
Know how to draw and show how a plane near produces an image that is the same size as the reflected object
Page 222 figure 7.16, 7.17 and 7.18
Explain what causes refraction of light rays.
Refraction of light rays happen when the bending of light travels to one medium to another.
The bending of light as it passes from one medium to another
Refraction
Can be transformed to chemical, thermal and electrical energy
Light
Allowing no light to pass through
Opaque
An artificial light source
Incandescent bulb