Chapter 9: Light, Colour & Radiant Energy

Question 1

What can refract light into different colours?

Answer 1

Prism

Question 2

What is the range of colours present in white light called?

Answer 2

The spectrum

Question 3

What are the 7 main colours (ROY G BIV) called? Give an example

Answer 3

Solar Spectrum

Rainbow

Question 4

What creates a rainbow?

Answer 4

Light refracted through a rain drop

Question 5

What happens to light when it strikes an object?

Answer 5

Reflected
Refracted
Absorbed

Question 6

What colour do we see when all colours are reflected?

What colour do we see when all colours are absorbed?

Answer 6

I. White

II. Black

Question 7

Why in blue light would a tomato look black?

Answer 7

Because the tomato would absorb all the blue and have no red or green to reflect back.

Question 8

What are the three additive primary colours?

Answer 8

Red
Blue
Green

Question 9

What are the secondary colours?

Answer 9

Yellow
Magenta
Cyan

Question 10

Why are red, blue and green called the additive primary colours?
Why are cyan, magenta and yellow called secondary colours?

Answer 10

Because together they make white light

Because they are made up of the additive primary colours

Question 11

What are the cells that respond to light called?

Answer 11

Rods and cones

Question 12

How do rods and cones work?

Answer 12

Rods respond to the presence of light.

There are three different types of cones cells each responding to a different colour (red, blue, green)

Question 13

What is it called if you have a difficulty detecting some colours?

Answer 13

Colour blindness

Question 14

What are the secondary colours also called and why?

Answer 14

Subtractive primary colours because they are missing a paret of the white light.
Cyan = Green+Blue (-Red)
Magenta = Red+Blue (-Green)
Yellow = Red+Green (-Blue)

Question 15

How does light travel?

Answer 15

Wave

Question 16

What is the high part of the wave called?

What is the low part of the wave called?

Answer 16

Crest

Trough

Question 17

What is the distance from crest to crest or trough to trough called?

Answer 17

Wave Length

Question 18

Define Amplitude

Answer 18

The height of the crest or the depth of the trough. Is the maximum distance from sea level

Question 19

Frequency

Answer 19

The number of complete cycles per second, measured in hertz.

Question 20

What is the model of light?

Answer 20

It is an idea of how light moves formed by scientist, it is not perfect but it helps our understanding

Question 21

True or False

Waves spread out more when their wave length is wider?

Answer 21

False

Waves spread out more when their wave length is longer
Conversly, they spread out less when their wave length is shorter

Question 22

Why is the sky red and orange at sunset?

Answer 22

Because the wavelengths are longer, The shorter wave lengths are typically deflected away

Question 23

What does LASER stand for

Answer 23

Light
Amplification
Stimulated
Emission
Radiation

Question 24

When light is _______ is has only one wave length

Answer 24

Coherent

Question 25

Where does the color come from?

Answer 25

White Light

Question 26

Give five uses for LASERs

Answer 26

i. Read barcodes at the supermarket ii. Sensing tiny pits on discs iii. See how fast a car is going iv. Surgery v. Cut through metal

Question 27

Why is it called the electromagnetic field?

Answer 27

Because electric and magnetic fields vibrate in a light wave.

Question 28

Different colours have different____ and _____. | What colour has the longest wave length? What colour has the shortest?

Answer 28

Frequencies Wavelengths Red Purple

Question 29

What is infrared light?

Answer 29

Visible light with a slightly longer wavelength It is used to warm food and baby animals Infrared sensors are used for burglar alarms and night vision googles.

Question 30

Radio waves

Answer 30

Longest wave. It is an infrared ray stretched out.

Question 31

Microwaves

Answer 31

The have the shortest wavelength and hight frequency of any radio wave.

Question 32

Ultraviolet waves

Answer 32

If you made violet waves a little shorter you would have ultraviolet waves. These waves can be harmful to the skin and cornea. The ozone layer helps protect us from ultraviolet waves. Bees can see these waves

Question 33

X rays

Answer 33

X rays are even shorter with a shorter wave length that ultraviolet. They penetrate through skin and muscle to the bone. This can be bad because they get absorbed into the bone which isn't healthy.

Question 34

Gamma Rays

Answer 34

They have the shortest wave length and can kill cancerous cells. They result from nuclear reactions.