Progressive And Stationary Waves

Question 1

What is a progressive wave

Answer 1

Transfers energy without transferring material and is made up of particles of a medium oscillating

Question 2

What is amplitude

Answer 2

A waves max displacement from the equilibrium position

Question 3

What are the units for amplitude

Answer 3

m

Question 4

What is frequency

Answer 4

The number of complete oscillations passing through a point per second

Question 5

What are the units for frequency

Answer 5

Hz

Question 6

What is wavelength

Answer 6

The length of one whole oscillation

Question 7

What is the unit for wavelength

Answer 7

m

Question 8

What is the speed

Answer 8

Distance travelled by the wave per unit time

Question 9

What is the unit of speed

Answer 9

m/s

Question 10

What is phase

Answer 10

The position of a certain point on a wave cycle

Question 11

Why are the units for phase

Answer 11

Radians, degrees or fractions of a cycle

Question 12

What is phase difference

Answer 12

How much a particle/wave lags behind another particle/wave

Question 13

What are the units for phase difference

Answer 13

Radians, degrees or fractions of a cycle

Question 14

What is a period

Answer 14

Time taken for one full oscillation

Question 15

When are two point in phase

Answer 15

If they are both at the same point of the wave cycle they will have the same displacement and velocity and their phase difference will be a multiple of 360°

Question 16

If two points are in phase what do they need to have the same out of frequency amplitude and wavelength

Answer 16

Frequency and wavelength

Question 17

When are two points out of phase

Answer 17

When they are a half cycle apart (180°)

Question 18

What is the equation for the speed of a wave

Answer 18

Speed = frequency x wavelength

Question 19

What is the equation for the frequency of a wave

Answer 19

Frequency = 1/period

Question 20

What are transverse waves

Answer 20

Oscillations of particles is at right angles to the direction of energy transfer

Question 21

Are electromagnetic waves longitudinal or transverse

Answer 21

Transverse

Question 22

What speed to electromagnetic waves travel at

Answer 22

3 x10 ^8

Question 23

How can transverse waves be demonstrated

Answer 23

By shaking a slinky vertically or through the waves seen on a string when attached to a signal generator

Question 24

What are longitudinal waves

Answer 24

Oscillations of particles is parallel to the direction of energy transfer

Question 25

What are longitudinal waves made out of

Answer 25

Compressions and rarefractions

Question 26

How can a longitudinal wave be demonstrated

Answer 26

By pushing a slinky horizontal

Question 27

what is a polarised wave

Answer 27

a transverse wave that oscillates in only one plane

Question 28

what does polarisation provide evidence for

Answer 28

the evidence for the nature of transverse waves because polarisation can only occur if a waves oscillations are perpendicular to its direction of travel

Question 29

how do polarised sunglasses reduce glare

Answer 29

by clocking partially polarised light reflected from water or tarmac as they only allow oscillations in the plane of the field making it easier to see

Question 30

how do TV and radio signals use polarisation to work

Answer 30

they plane polarised by the orientation of the rods on the transmitting aerial so the receiving ariel must be aligned in the same plane of polarisation to receive the signal at full strength

Question 31

what is superposition

Answer 31

is where the displacements of two waves are combined as they pass each other

Question 32

what is the resultant displacement in superposition

Answer 32

is the vector sum of each waves displacement

Question 33

what are the two types of interference

Answer 33

constructive and destructive

Question 34

how does constructive interference occur

Answer 34

occurs when 2 waves have displacement in the same direction

Question 35

how does destructive interference occur

Answer 35

occurs when on wave has positive displacement and the other has a negative displacement

Question 36

what needs to happen to get total destructive interference

Answer 36

when the waves have equal but opposite displacements

Question 37

what does a stationary wave form from and what needs to be the same

Answer 37

the superposition of 2 progressive waves travelling in opposite directions in the same plane with the same frequency, wavelength and amplitude

Question 38

do stationary waves transfer energy

Answer 38

no

Question 39

when waves meet in phase which interference occurs and what forms there

Answer 39

constructive interference and antinodes are formed

Question 40

when waves meet out of phase which interference occurs and what forms there

Answer 40

destructive interference and nodes are formed there

Question 41

what are antinodes

Answer 41

regions of maximum amplitude

Question 42

what are nodes

Answer 42

regions of no displacement

Question 43

what is an example of how to form a stationary wave

Answer 43

a string fixed at one end and the other end fixed to a driving oscillator

Question 44

how does a stationary wave form when fixed at one end and the other fixed to a driving oscillator

Answer 44

a wave travelling down the string from the oscillator will be reflected at the fixed end of the string and travel back along the string causing superposition of the two waves and because the waves have the same wavelength frequency and amplitude a stationary wave is formed

Question 45

what is the lowest frequency at which a stationary waves formed called

Answer 45

the first harmonic

Question 46

how many nodes and antinodes are in the first harmonic

Answer 46

two nodes and one antinode

Question 47

how do you find the frequency of the second harmonic from the first

Answer 47

double it

Question 48

how are stationary microwaves formed

Answer 48

by reflecting a microwave beam at a metal plate to find the nodes and antinodes use a microwave probe

Question 49

how are stationary sound waves formed

Answer 49

can be formed by placing a speaker at one end of the closed glass tube lay powder across the bottom of the tube it will be shaken at the antinodes and settle at the nodes as you then know the frequency and wavelength you can work out speed of sound