P5 EM Spectrum

Question 1

What is the correct order of wavelengths

Answer 1

Radio, micro, infra-red, visible, ultra violet, X-ray, gamma

Question 2

Order of colours from low energy to high

Answer 2

Red, orange, yellow, green, blue, indigo, violet

Question 3

Total internal reflection

Answer 3

Happens when a wave is travelling from a more dense to a less dense material, if the angle of incident is greater than the critical angle for that material it will be fully reflected back into the material, not refracted through

Question 4

Specular reflection

Answer 4

When a wave reflects of a smooth surface and all of it reflects ht same so an image can be seen from the reflection, done by a mirror

Question 5

Diffuse reflection

Answer 5

When a wave reflects off a ruff surface and lots of waves are reflected in different directions

Question 6

A red shirt appears red because

Answer 6

It reflects the red wavelengths of light and absorbs the other wavelengths of visible light

Question 7

A red filter makes light red because

Answer 7

The red wavelengths of light will transmit through but the other wavelengths will be absorbed

Question 8

Converging lens

Answer 8

Convex, focuses light in front of the lens, a powerful lens is thicker and has a shorter focal legnth

Question 9

Diverging lens

Answer 9

Concave, focuses the light behind the lens creating a virtual image, not a real one. More powerful lenses are thicker and spread out the light more

Question 10

How do you create virtual images with lenses

Answer 10

Diverging lenses always focus the light behind the lens and so always create virtual images, converging lenses will only focus behind the lens if the object is closer than the focus of the lens

Question 11

How to create real images with lenses

Answer 11

Only converging lenses will focus the image in front of the lens, if the object is further than the focus of the lens

Question 12

Uses of radio waves

Answer 12

Broadcasting, communications and satellite transmissions

Question 13

Uses of micro waves

Answer 13

Cooking, communication(satellite transmission), mobile phones

Question 14

Uses of infra-red

Answer 14

Short range communication, e.g. TV remotes, cooking, thermal imaging, security systems(IR trip wires), fibre optics

Question 15

Uses of visible light

Answer 15

Visio, photography, illumination

Question 16

Uses of UV

Answer 16

Fluorescent lighting, sterilising food and medical equipment, used by the body to help create vitamin D, security markings, detecting forged bank nootes

Question 17

Uses of X-rays

Answer 17

Medical imaging, radiotherapy, airport security scanners

Question 18

Uses of gamma rays

Answer 18

Medical imaging(CT scans), sterilising food/ medical equipment, radiotherapy

Question 19

Dangers of radio waves

Answer 19

They are harmless

Question 20

Dangers of micro waves

Answer 20

Boils water, so can be dangerous and harm internal organs

Question 21

Dangers of infra-red waves

Answer 21

Burns

Question 22

Dangers of visible light

Answer 22

High quantities can damage the retina

Question 23

Dangers of UV waves

Answer 23

Can cause skin cancer

Question 24

Dangers of X-rays

Answer 24

Can cause cancer

Question 25

Danger of gamma waves

Answer 25

Can cause cancer

Question 26

Formula to work out the power of a lens

Answer 26

P=1/f P=optical power in diopters, f = focal legnth

Question 27

How are radio waves created

Answer 27

Electrons in a circuit are made to oscillate (move back and forward in a closed circuit), the vibrations from which emits radio waves

Question 28

How are radio waves picked up

Answer 28

Radio waves cause electrons in circuits on the detectors to oscillates, these oscillations are pick up

Question 29

What do powerful lenses look like?

Answer 29

thicker so can refract light more