Properties of waves

Question 1

what are waves one of the ways of?

Answer 1

transferring energy between stores

Question 2

what can waves be described as?

Answer 2

oscillations

Question 3

define ‘oscillation’:

Answer 3

vibrating

Question 4

what is the difference between the direction of the oscillations in longitudinal and transverse waves?

Answer 4

• longitudinal waves, vibrations are parallel to direction of wave travel.
• tranverse waves, the vibrations are at right angles to direction of wave travel.

Question 5

what do mechanical waves cause? and what is their limitation (kind of)?

Answer 5

Mechanical waves cause oscillations of particles in a solid, liquid or gas
-must have a medium to travel through

Question 6

what happens once a wave has passed through?

Answer 6

the medium ends up back in its rest position.

Question 7

what do electromagnetic waves cause? and what are they all?

Answer 7

Electromagnetic waves cause oscillations in electrical and magnetic fields.
-transverse.

Question 8

what do all waves transfer?

Answer 8

energy but they do not transfer matter.

Question 9

define ‘rest position’

Answer 9

the undisturbed position of particles or fields when they are not vibrating.

Question 10

define ‘displacement’

Answer 10

the distance that a certain point in the medium has moved from its rest position.

Question 11

define ‘peak’

Answer 11

the highest point above the rest position

Question 12

define ‘trough’

Answer 12

the lowest point below the rest position

Question 13

define ‘amplitude’

Answer 13

the maximum displacement of a point of a wave from its rest position.

Question 14

define ‘wavelength’

Answer 14

distance covered by a full cycle of the wave. Usually measured from peak to peak, or trough to trough

Question 15

define ‘time period’

Answer 15

the time taken for a full cycle of the wave. Usually measured from peak to peak, or trough to trough

Question 16

define ‘Frequency’

Answer 16

the number of waves passing a point each second.

Question 17

examples of a longitudinal wave: (3)

Answer 17

sound waves
ultrasound waves
seismic P-waves

Question 18

what do longitudinal waves show?

Answer 18

areas of compression and rarefaction

Question 19

define ‘compressions’

Answer 19

regions of high pressure due to particles being close together

Question 20

define ‘rarefactions’

Answer 20

regions of low pressure due to particles being spread further apart

Question 21

describe the movement/ transportation of particles in a longitudinal wave: (2)

Answer 21

none of the particles are transported along a longitudinal wave.
-they move backwards and forwards between compressions as the wave is transmitted through the medium.

Question 22

examples of transverse waves: (4)

Answer 22

-ripples on the surface of water
-vibrations in a guitar string
-electromagnetic waves – eg light waves, microwaves, radio waves
seismic S-waves

Question 23

describe the movement/ transportation of particles in a transverse wave: (2)

Answer 23

none of the particles are transported along a transverse wave.
-particles move up and down as the wave is transmitted through the medium.

Question 24

One way to remember the movement of particles in longitudinal waves: ‘P sound’

Answer 24

longitudinal waves such as seismic P-waves may be thought of as Pressure or Push waves as the particles move Parallel to the wave.

Question 25

One way to remember the movement of particles in transverse waves: ‘S sound’

Answer 25

transverse waves such as seismic S-waves may be thought of as Shake or Shear waves as the particles move from Side-to-Side – croSSing the direction of wave travel.

Question 26

equation for time period of a wave: (word and symbol)

Answer 26

time period (s) = 1 / frequency (hz)

T = 1/ f

Question 27

equation for wave velocity (or speed): (word and symbol)

Answer 27

wave speed (m/s) = frequency (Hz) × wavelength (m)

v = f x λ

Question 28

what is λ?

Answer 28

lambda, which is wave length

Question 29

what is sound (in terms of a wave)?
how is this wave passed on?
what does the speed of the wave depend on?

Answer 29

• sound is a mechanical longitudinal wave.
• by collisions between particles
• density of the particles.

Question 30

what happens when sound moves from one medium into another?
what will this also result in?
what about frequency?

Answer 30

speed changes
a change in wavelength
frequency is unaffected.