Visible Light And Colour

Question 1

Speculation reflection

Answer 1

When all light rays that hit a mirror reflect in the same direction or parallel
Only on a smooth surface
Creates an image

Question 2

Diffuse reflection

Answer 2

On a rough surface
When rays hit and reflect at different angles to each other (parallel)
They do not produce an image

Question 3

How do colour filters work?

Answer 3

Absorbing specific wavelengths (colours) and transmitting certain wavelengths
Eg red filter absorbs other colours but transmits red

Question 4

Transparent

Answer 4

An object that transmits visible light
Clearly see through eg wine glass or glass windows

Question 5

Translucent

Answer 5

Scatter light rays
So we can’t see through clearly
Eg bathroom windows

Question 6

Opaque

Answer 6

Objects we can’t see through

Question 7

What determines the colour of an opaque object

Answer 7

What colour it reflects
Eg red object reflects red but absorbs all other colours

Question 8

What determines a white opaque object?

Answer 8

It reflects all wavelengths of visible light
So reflects all colours

Question 9

What determines a black opaque object?

Answer 9

Absorbs all wavelengths of visible light

Question 10

What happens if you put a colour filter over a coloured object?

Answer 10

If they are the same colour = you will see the object as it’s true colour

If they are different, you will see objects colour as black
Because the filter only allows a certain wavelength (colour) to be transmitted which is absorbed by the different coloured object
So it doesn’t reflect any light = absorption

Question 11

What objects will absorb infrared radiation?

Answer 11

All no matter the colour or temperature
However matte black does it the best

Question 12

What objects will emit infrared radiation?

Answer 12

All no matter the temperature
But hot objects do it best in a given time

Question 13

What does the wavelength and intensity of the infrared radiation depend on?

Answer 13

The temperature of object
Very hot objects = emit short wavelength
Cool objects = long wavelengths

Very hot objects = more intense radiation

Question 14

Why do very hot objects emit visible light?

Answer 14

Because it emits shorter wavelengths
Thus emitting wavelengths close or within visible light spectrum

Question 15

What is a black body?

Answer 15

All radiation is absorbed
None is reflected not passes through
Because good at emitting = good at absorbing
It also is best possible emitter

Question 16

What happens if an object is warmer than its surroundings?

Answer 16

It will emit more radiation than it absorbs
Therefore it will decrease in temperature

Question 17

What happens if an object is cooler than its surroundings?

Answer 17

It will absorb more radiation than it emits
Thus increases in temperature

Question 18

What happens if an object is at a constant temperature

Answer 18

It absorbs and emits radiation at the same rate

Question 19

What does the sun emit?

Answer 19

Short wavelength radiation eg visible light and ultraviolet

Question 20

What does the Earth respond to radiation from sun

Answer 20

Some reflected in clouds
Remaining absorbed by surface of Earth
Thus surface temp increases
and can reflect it back into space
However some trapped by greenhouse gases