Working With Waves

Question 1

What is the crest of a wave?

Answer 1

The top of the wave

Question 2

What is the trough of a wave?

Answer 2

The bottom of the wave

Question 3

What is a period in waves

Answer 3

The time between two crests of a wave

Question 4

What is the principal of superposition mean?

Answer 4

When waves from 2 sources arrive at the same place then they add together

Question 5

What does constructive interference mean for a wave?

Answer 5

If the two waves are the same than the wave gets bigger so it’s louder

Question 6

What does destructive interference mean for a wave?

Answer 6

If the waves are opposite they are in anti-phase so they cancel each other out making the wave smaller

Question 7

What is it called when the wave is in phase

Answer 7

Constructive interference

Question 8

What is it called when the wave is in anti-phase?

Answer 8

Destructive interference

Question 9

What is the speed of light?

Answer 9

3x10⁸

Question 10

What is the wave speed of c

Answer 10

3x10⁸

Question 11

What is the speed of a radio wave?

Answer 11

3x10⁸

Question 12

What are the two types of waves?

Answer 12

Transverse and longitudinal

Question 13

What is frequency measured in?

Answer 13

Hertz (Hz)

Question 14

How do you work out frequency

Answer 14

Wavelength divided by time

Frequency= Wavelength/time (s)

Question 15

How does amplitude affect light

Answer 15

High amplitude brighter light

Question 16

How does amplitude affect light

Answer 16

High amplitude brighter light

Question 17

How does frequency affect light and sound

Answer 17

Sound higher pitch

Different colours for light

Question 18

What is the compression part of a longitudinal wave

Answer 18

When the waves are close together

Question 19

What is the rare fraction part of a longitudinal wave

Answer 19

When the waves are furthest apart

Question 20

How do you work out wave speed and units

Answer 20

Wave speed (ms-¹) = frequency x wavelength
                                        f (Hz) x Lambda (metres)

Question 21

How do you work out waves speed with distance and time

Answer 21

Wave speed equals distance divided by time

Distance/time

Question 22

How do you work out circumference with radians

Answer 22

2pieRadians

Question 23

What is a radian

Answer 23

One radian is the angle of an arc that is equal to the radius

Question 24

What is diffraction

Answer 24

The spreading out of a way when passing for a barrier

Question 25

What affects the diffraction angle

Answer 25

The diffraction angle increases as the width of the gap decreases

The most diffraction happens when gap = wavelength

Question 26

What is the interference pattern

Answer 26

Constructive interference and destructive interference makes beams of the light which have darkness in between them

Question 27

How can you measure wavelength

Answer 27

Using diffraction grating

Question 28

How does diffraction grating work

Answer 28

Lots of little slits nanometres apart

the light goes through the slits and at certain angles we get constructive interference and destructive interference

Question 29

How do we measure the wavelength using the angles, how does it work?

Answer 29

A certain angles for you get constructive interference and destructive interference

At these angles for path difference of the rays, from the different slits make the wavelength for a particular colour

Question 30

What happens when atoms get excited

Answer 30

They in it light as photons

Question 31

What do elements do and they get excited

Answer 31

Atoms of different elements in different wavelengths/colours of light

if I observe the emission spectrum of a substance we can identify what elements it contains

Question 32

What does oscillation mean?

Answer 32

Regular repeating motion

Question 33

What is Resonance?

Answer 33

When 2 things vibrate at the same frequency e.g a string on an instrument.

Question 34

What does a stationary wave mean?

Answer 34

Stationary waves means no sideways movement. It oscillates between the 2.

Question 35

What does a node mean on a wave

Answer 35

Zero displacement of the wave

Question 36

What does an antinode mean on a wave

Answer 36

The maximum displacement of the wave

Question 37

What does superposition mean?

Answer 37

Superposition refers to when the waves line up the peak on peak, to create a bigger wave (higher amplitude)

Question 38

What does compression in longitudinal waves mean

Answer 38

when the waves are close together

Question 39

What does refraction in longitudinal waves mean

Answer 39

when the waves are far apart

Question 40

What are the first harmonics called?

Answer 40

First 8 are called as octaves

Question 41

What is the first harmonic known as?

Answer 41

fundamental frequency

Question 42

What is the wavelength what the fundamental frequency?

Answer 42

½ λ

Question 43

What are all sound waves?

Answer 43

longitudinal waves

Question 44

When is resonance useful?

Answer 44

Instruments
Water molecules resonate in microwaves to heat food
TV aerials use resonance to get a stronger signal

Question 45

When is resonance a problem?

Answer 45

Wind could make buildings such as produce oscillate dangerously

Earthquakes can make buildings oscillate

If machinery resonates it could break e.g washing machines

Question 46

Why are stationary waves only seen at certain frequencies?

Answer 46

Strings have a series of natural frequencies

Corresponding to a number of half wavelength

A stationary wave is produced only when the frequency of the vibration generator produces waves of those wavelengths

Question 47

Give one use of fibre optics in medicine?

Answer 47

Endoscopy

Endoscopes

Question 48

Why is there total internal reflection in an optical fibre?

Answer 48

Fibre optic cable denser than outside/air

Therefore incidence at boundary/reflection

At greater than the critical angle