Topic 5 - Light and the EM spectrum

Question 1

#Colours

How is an apple red (talking about light rays)

Answer 1

White light hits the apple and only red light is reflected, the rest are absorbed

Question 2

#Colours

What do colour filters do

Answer 2

Colour filters only allow certain wavelengths of light to travel through them so that only some colours are transmitted, while the rest are absorbed

Question 3

#Colours

What colour would a red hat look like through a blue filter?

Answer 3

Black because the red light will be absorbed by the filter so the hat will have no colour.

Question 4

#Lenses

What are the 2 types of lenses and what do they do?

Answer 4

1. Converging/Convex lens - Refracts rays inwards creating a real image
2. Diverging/concave lens - Refracts rays outwards creating a virtual image

The more curved the lens is, the higher the refractive power of the lens

Question 5

#Lenses

What is the principle focus of a diverging lens and focal length

Question 6

#Lenses

What is the principle focus and focal length of a converging lens

Question 7

#Lenses - virtual images

Where are images formed

Answer 7

At the point where all of the light rays meet.

Question 8

#Lenses - virtual images

What is a real image?

Answer 8

A real image is formed when light rays **come together **and the image can be captured on a screen.

Question 9

#Lenses - virtual images

What is a virtual image?

Answer 9

An image where the rays **do not **actually come to a point, and therefore cannot be captured on a screen, only tracked back to the original object.

Question 10

#EM Waves

What type of waves are EM waves?

Answer 10

Transverse

Question 11

#EM Waves

At what speed do EM waves travel in a vaccum?

Answer 11

Speed of light

Question 12

#EM Waves

All EM waves transfer energy from a ________________________________ to a ____________________________________. Give some examples

Answer 12

All EM waves transfer energy from a source to an absorber.
For example, you are heated via infrared radiation (absorber) by a an electric heater (source) from its thermal energy store to yours.

Question 13

#EM Waves

What is the order of the EM spectrum in descending order of wavelength?
Use an acronym to support you.

Answer 13

Radioactive Man Improves Vision Using X-ray Goggles

Radio waves
Micro waves
Infrared
Visible
Ultraviolet
X-rays
Gamma rays

Question 14

EM Waves

At what speed do EM waves travel in different materials?

Answer 14

Varies based on the material