Visible Light And Colour

Question 1

why do we see the colour blue

Answer 1

• white light is a combination of colours
• when that light hits a surface, all of the waves apart from blue get absorbed
• and the wavelength for blue gets reflected back

Question 2

what is a colour filter

Answer 2

a transparent body that allows light of only certain colours to pass through it (be transmitted)

Question 3

what is white light

Answer 3

a mixture of all the colours of light which all have different wavelengths

Question 4

what is colour about

Answer 4

the difference in absorption, transmission and reflection of different wavelengths by different mateirals

Question 5

what are opaque objects

Answer 5

• objects that dont transit light

- when visible light waves hit them, they absorb some wavelengths of light and reflect others

Question 6

what does the colour of an opaque object depend on

Answer 6

• which wavelengths of light are reflected
• a red apple appears to be red because the wavelengths corresponding to the red part of the visible spectrum are reflected

Question 7

what are the only colours that you cant make by mixing

Answer 7

• the primary colours

- which are pure red, green and blue

Question 8

if colours can mix together to make different colours, why would a banana look yello

Answer 8

• yellow isnt a primary colour
• so it could look yellow because its reflecting yellow light
• or because its reflecting both red and green light

Question 9

what do white objects do

Answer 9

they reflects all wavelengths of visible light equally

Question 10

what do black objects do

Answer 10

they absorb all wavelengths of visible light

Question 11

what do transparent and translucent objects do and how does it work

Answer 11

• they can transmit light
• which means that all light that hits the surface of the object isnt absorbed or reflected
• some of it passes through

Question 12

what does a primary colour filter do

Answer 12

it only transmits its primary colour

Question 13

if you held a red object behind a blue filter, what would it look like and why

Answer 13

• the object would look black
• because the wavelength being reflected from the object is on the red part of the spectrum
• but the filter only allows wavelengths of blue light to transmit through it
• so the red light would be absorbed by the filter
• which leads to no other wavelengths of light being able to be passed through, so ti would look black

Question 14

what are filters that arent for primary colours do

Answer 14

• they let through both the primary wavelengths of light corresponding to that wavelength of light
• so the wavelengths of the primary colours are added together to make that colour

Question 15

if cyan is made from the colours blue and green what colours would a cyan filter transmit

Answer 15

• the wavelength for green
• the wavelength for blue
• and the wavelength for cyan