3- Waves

Question 1

What are transverse waves?

Answer 1

Waves where the vibrations are at 90° to the direction of wave travel

Question 2

What are longitudinal waves?

Answer 2

Waves where the vibrations are parallel to the direction of wave travel

Question 3

What do all waves do?

Answer 3

Transfer energy but NOT matter

Question 4

Can transverse waves move in a vacuum?

Answer 4

Some can

Question 5

Can longitudinal waves move in a vacuum?

Answer 5

No

Question 6

What can transverse waves move in?

Answer 6

Solids + liquids

Question 7

What are examples of transverse waves?

Answer 7

• ripples on water
• X rays
• light

Question 8

What are examples of longitudinal waves?

Answer 8

• sound waves
• ultrasound waves
• P- waves

Question 9

What can longitudinal waves move in?

Answer 9

Solids, liquids + gases

Question 10

What is amplitude?

Answer 10

The distance from the undisturbed position to the peak or trough of a wave

Question 11

What is wavelength?

Answer 11

The distance from 1 point on the wave to the same point on the next wave

Question 12

What is frequency ?

Answer 12

The number of waves passing a point in a second

Question 13

What is the time period?

Answer 13

The time taken for a single wave to pass a point

Question 14

Wavefronts close together = ?

Answer 14

Short wavelength

Question 15

Wavefronts far apart = ?

Answer 15

Long wavelength

Question 16

What is the Doppler effect ?

Answer 16

The apparent change In wavelength and frequency of a wave emitted by a moving source

Question 17

What are Electromagnetic waves ?

Answer 17

Transverse waves that transfer energy from the source of the waves to an absorber

Question 18

What are the properties of EM waves ?

Answer 18

• transverse
• can all travel through a vacuum at the same speed
• transfer energy

Question 19

What are radio waves used for + why ?

Answer 19

Long range communication - can be reflected from the earth”s atmosphere

Question 20

What are micro waves used for + why ?

Answer 20

Satellite communications + cooking - can penetrate earths atmosphere

Question 21

What are infrared waves used for + why ?

Answer 21

Optical fibre communication- can undergo total internal reflection

Question 22

What is visible light used for + why ?

Answer 22

Taking pics + vids- camera can detect visible light

Question 23

What is ultraviolet used for ?

Answer 23

Detecting security ink

Question 24

What are X-rays used for + why ?

Answer 24

To photograph bones- can penetrate soft tissues

Question 25

What are gamma rays used for + why ?

Answer 25

To sterilise medical tools- gamma kills bacteria

Question 26

Name everything in the EM spectrum from longest wavelength to shortest:

Answer 26

Radio waves, microwaves, infrared, visible light, ultraviolet, x-rays, gamma rays

Question 27

Why is radiation with higher energy harmful?

Answer 27

Highly ionising: harmful to cells + tissues causing cancer

Question 28

higher frequency = ?

Answer 28

Higher energy of radiation

Question 29

In the visible light spectrum, which colour has the longest + shortest wavelength?

Answer 29

Longest - red (lowest frequency) | Shortest- violet (highest frequency)

Question 30

Increase in wavelength = ?

Answer 30

Decrease in frequency

Question 31

Decrease in wavelength = ?

Answer 31

Increase in frequency

Question 32

Shorter wavelength = ?

Answer 32

More ionising (dangerous)

Question 33

What can sound undergo?

Answer 33

Reflection + refraction

Question 34

What is reflection?

Answer 34

When a wave hits a boundary between 2 media + does not pass though but stays in the original medium

Question 35

What is refraction ?

Answer 35

When a wave or light ray moves from one medium to another + its speed changes

Question 36

From less dense material to more dense = ?

Answer 36

Light bends TOWARDS normal

Question 37

From more dense material to less dense = ?

Answer 37

Light bends AWAY from the normal

Question 38

More optically dense = ?

Answer 38

Higher refractive index

Question 39

Less optically dense = ?

Answer 39

Lower refractive index

Question 40

When does total internal reflection occur?

Answer 40

- when the angle of incidence is greater than the critical angle - when the incident material is denser than the second material

Question 41

What are the two uses for total internal reflection?

Answer 41

- Optical fibres | - periscopes

Question 42

What is the critical angle

Answer 42

When the angle of refraction is exactly 90°