P5 EM Spectrum Flashcards Preview

Physics > P5 EM Spectrum > Flashcards

Flashcards in P5 EM Spectrum Deck (29):
1

What is the correct order of wavelengths

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

2

Order of colours from low energy to high

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

3

Total internal reflection

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

4

Specular reflection

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

5

Diffuse reflection

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

6

A red shirt appears red because

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

7

A red filter makes light red because

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

8

Converging lens

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

9

Diverging lens

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

10

How do you create virtual images with lenses

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

11

How to create real images with lenses

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

12

Uses of radio waves

Broadcasting, communications and satellite transmissions

13

Uses of micro waves

Cooking, communication(satellite transmission), mobile phones

14

Uses of infra-red

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

15

Uses of visible light

Visio, photography, illumination

16

Uses of UV

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

17

Uses of X-rays

Medical imaging, radiotherapy, airport security scanners

18

Uses of gamma rays

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

19

Dangers of radio waves

They are harmless

20

Dangers of micro waves

Boils water, so can be dangerous and harm internal organs

21

Dangers of infra-red waves

Burns

22

Dangers of visible light

High quantities can damage the retina

23

Dangers of UV waves

Can cause skin cancer

24

Dangers of X-rays

Can cause cancer

25

Danger of gamma waves

Can cause cancer

26

Formula to work out the power of a lens

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

27

How are radio waves created

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

28

How are radio waves picked up

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

29

What do powerful lenses look like?

thicker so can refract light more