Physics Flashcards Preview

English > Physics > Flashcards

Flashcards in Physics Deck (22):
1

Type 2
Non-luminous

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

2

Incandescence

Light given off due to high temperatures

3

Fluorescence

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

Phosphorescence

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

Chemiluminesence

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

6

Bioluminescence

When living things produce light (fire fly)

7

Triboluminescent

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

8

LEDs

Light emitting diodes

9

How LEDs work

-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

Why LEDs are the best

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

11

Lasers

Light amplification by stimulated emission of radiation

12

Use for lasers

-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

What is light

-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

Fusion

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

What does rectilinear propagation mean

Light travels very fast in a straight line

16

Sharp shadows the objects is

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

17

Fuzzy shadows the objects is

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

18

What happens when light strikes an object: ( 3 ways)
-transparent
-translucent
-opaque

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

Salt

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

20

Regular specular reflection of light:

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

21

Diffuse reflection of light:

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

22

Type 1
Luminous

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