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Flashcards in Physics Deck (22)
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1
Q

Type 2

Non-luminous

A

An object that does not give off its own light (moon)

2
Q

Incandescence

A

Light given off due to high temperatures

3
Q

Fluorescence

A

Chemical that gives off light when hit by invisible high energy waves-uv Rays hit the fluorescent coating and turn into visa me light

4
Q

Phosphorescence

A

Phosphorus absorbs the light rays and gives off visible light. -bedroom stars

Chemicals that give off light when hit by high energy light waves, and stay luminous for long periods of time. (Glow in the dark)

5
Q

Chemiluminesence

A

Chemical reactions that give off light with next to no heat (glow sticks)

6
Q

Bioluminescence

A

When living things produce light (fire fly)

7
Q

Triboluminescent

A

When certain crystals (sugar) are scratched , crushed or rubbed together light can be produced (life savers)

8
Q

LEDs

A

Light emitting diodes

9
Q

How LEDs work

A
  • small lights that do not get too hot when they give off light.
  • they are made of small crystals of silicon that light up when electricity flows in the proper direction,
10
Q

Why LEDs are the best

A

1- DONT waste energy for heat
2- don’t contain mercury
3- last along time

11
Q

Lasers

A

Light amplification by stimulated emission of radiation

12
Q

Use for lasers

A
  • very bright (intense)
  • the light is all the same colour (electromagnetic waves of the same energy level)
  • the light stays together as a beam (unison)
  • scanners, exrays, phones, computers,
13
Q

What is light

A
  • a wave of electric and magnetic fields
  • wave of energy- shown to be particle like in nature
  • energy can vibrate atoms and electrons which can release this energy as visible through colour
14
Q

Fusion

A

Tremendous amount of energy
Light is needed for life
Emitted in all directions in a straight line
Speed- 300 000 000 meters per second (faster than sound)

15
Q

What does rectilinear propagation mean

A

Light travels very fast in a straight line

16
Q

Sharp shadows the objects is

A

Farther away from the source. It is small compared to the source

17
Q

Fuzzy shadows the objects is

A

Close to the light source. Object is small compared to the source.

18
Q

What happens when light strikes an object: ( 3 ways)

  • transparent
  • translucent
  • opaque
A

1) reflected 2) absorbed 3) transmitted
- all light rays pass through (glass)
- some light rays pass through (frosted glass)
- no light can go through (card board)

19
Q

Salt

A

Size - smaller, larger, same
Attitude - upright, inverted, latterly inverted
Location - at c, beyond c… Behind mirror
Type - virtual, real

20
Q

Regular specular reflection of light:

A

On shinny surfaces, light tends to reflect following the law of reflection. A clear image is seen

21
Q

Diffuse reflection of light:

A

On rough surfaces the reflection waves become irregular. The light tends to spread out in all directions and no clear image is formed.

22
Q

Type 1

Luminous

A

An object that gives off its own light (candle, fire, light bulb)