Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physics > Lecture 6 - What is colour? > Flashcards

Lecture 6 - What is colour? Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

What is wavelength?

A

(m)- the distance from one point on a wave to the same point on the successive wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Whatis frequency?

A

(Hz)- how many waves go by in 1 second

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is period?

A

(s)- how long a wave takes to go through the full range of motion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is light characterised by?

A

wavelength or its frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What can looking at the colour of a wave do?

A

help determine its frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is black?

A

absorb all frequencies of light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the different aspects of colour?

A

colour temp
blackbody radiator
non-blackbody radiators

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does thermal sources of light do?

A

emit radiant energy in proportion to their temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does the colour tell us when it emits?

A

tells us the temperature of the source

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where is the colour temperature commonly observed?

A

when a piece of metal is heated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What happens when you increase the temperature of the flame to the metal?

A

the metal will start to glow red

and when its very hot it will turn white and blue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a blackbody radiator?

A
  • a perfect blackbody is a theoretical object that would absorb all the radiation/wavelengths that falls on it
  • it would not reflect or transmit any radiation
  • best possible emitter and absorber of radiation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are non-blackbody radiator?

A

white and shiny silvery surfaces which are poor emitters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why are radiators in home usually painted white?

A

so that the infrared radiation is emitted gradually

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens if you increase temp in the blackbody curves?

A

there is a shift in wavelengths emitted

there is a shift towards shorter wavelengths

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What can you call blackbody radiators?

A

if a particular source radiates energy following those wavelengths (blackbody curve)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How can you specify a blackbody radiator?

A

by its colour temperature, in degrees Kelvin (K)

18
Q

What does it mean if you have a red (warm) lamp?

A

its colour temperature is LOW

19
Q

What does it mean if you have a cold (white) lamp?

A

it colour temperature is HIGH

20
Q

What do people prefer from home lamps?

A

a colder lamp which gives a warmer sensation/look(so red lamp)

21
Q

What do people prefer for work/office/school lamps?

A

a warmer lamp which gives a colder sensation/look (so white lamp)

22
Q

What system allows us to specify colours graphically?

A

CIE 1931 (x,y) colour space

23
Q

What does the CIE system do?

A

specify x,y,z co-ordinate on the chart- mixture of 3 CIE primaries called tristimulus values
they map a colour with respect to hue and saturation on a 2D CIE colour space

24
Q

What colour is more saturated?

A

the further away you are (to edges) the more saturated

25
Q

What are spectral colours?

A

one wavelength colour
they are aligned around the outside of the horse-shoe shape and are most saturated
can be correlated to a specific wavelength

26
Q

What colours are less saturated?

A

closer to the centre

27
Q

How can you make a colour?

A

by combining wavelengths

one colour can be made many different ways - from combinations of colours

28
Q

What is white light?

A

can be made of any mixture of different colours

in the middle of CIE spectrum

29
Q

What else is part of the CIE garph?

A

line of purples across the bottom.

30
Q

What else is part of the CIE garph?

A

line of purples across the bottom.

31
Q

What is additive colour mixing?

A

mixing lights of different wavelengths

superposition of red,blue,green lights which can be combined to make visibile light

32
Q

What are the primary colours?

A

red , green, blue which make whitw light

33
Q

What are the complementary colours for R,G,B?

A

Cyan
magenta
yellow

34
Q

What do computer monitors use?

A

additive colour mixing

35
Q

What is the triangle in the computer monitor?

A

the computer monitor can only produce those colours by mixing them in different combinations

36
Q

What do the 3 primaries in the computer monitor do?

A

produce the triangle

37
Q

What is the gamet determined by?

A

in chromaticity space, the gamet is determined by the triangle formed by the chromaticities of the light

38
Q

Maximum luminance?

A

determined by the sums of the R,G,B luminances

39
Q

What is a gamet?

A

all colours the display can produce

40
Q

What is subtractive colour mixing?

A

based on absorption or subtraction of certain wavelengths from white light.
as a result of absorbing different wavelengths of colours

41
Q

What are the usual colours in colour printing?

A

cyan, magenta, yellow, black

Physics (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions