Waves

Question 1

What do waves transfer/not transfer?

Answer 1

energy and information

not matter

(e.g. a water wave moves but a ball in the water doesn’t)

Question 2

What can waves be described as?

Answer 2

an oscillation or vibration around a rest/fixed position

Question 3

oscillation/vibration

Answer 3

repeated movement back and forth about a fixed point

Question 4

Name 5 properties that waves have

Answer 4

frequency

speed

wavelength and amplitude

(time) period

Question 5

frequency

Answer 5

number of waves passing a point per second

hertz (Hz)

Question 6

speed

Answer 6

how fast a wave moves

m/s

Question 7

wavelength

Answer 7

distance covered by a full cycle of the wave

distance between peak-peak or trough-trough of a wave

Question 8

amplitude

Answer 8

maximum displacement of a wave from its rest position

distance between the middle of the wave and the peaks/troughs

Question 9

(time) period

Answer 9

time taken for a full cycle of the wave

1/frequency

measured peak-peak or trough-trough

Question 10

rest position

Answer 10

undisturbed position of particles when they are not vibrating

Question 11

displacement

Answer 11

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

Question 12

peak

Answer 12

highest point above the rest position

or

number of waves passing a point each second

Question 13

trough

Answer 13

lowest point below the rest position

Question 14

longitudinal waves

Answer 14

a wave that moves in the same direction as the direction in which the particles are vibrating

Question 15

transverse waves

Answer 15

a wave that moves in a direction at right angles to the way in which the particles are vibrating

Question 16

direction of oscillations in longitudinal waves vs transverse waves

Answer 16

parallel to the direction of wave travel

right angles to the direction of wave travel

Question 17

2 examples of longitudinal waves

Answer 17

sound waves

seismic P waves

(particles in the material the sound is travelling through move back and forth in the same direction the sound is travelling)

Question 18

3 examples of transverse waves

Answer 18

water surface

electromagnetic waves (light)

seismic S waves

Question 19

medium

Answer 19

a material through which a wave can be transmitted

Question 20

mechanical waves

Answer 20

cause oscillations in a solid, liquid, or gas, and must have a medium to travel through

once the wave has passed the medium ends up where it started

can be longitudinal or transverse

Question 21

electromagnetic waves

Answer 21

cause oscillations in electrical and magnetic fields

are all transverse

Question 22

Give two ways in which longitudinal and transverse waves are

a) similar
b) different

Answer 22

a) both transfer energy without transferring matter
both have an amplitude, speed, wavelength, and frequency

b) particles in longitudinal waves vibrate along the direction of movement
particles in transverse waves move at 90 degrees to the direction of travel
they can have different speeds, frequencies and wavelengths

Question 23

a) Sketch a transverse wave and mark the amplitude and wavelength on it
b) Draw an arrow to show which way the wave moves
c) Draw a small particle on the wave, with arrows to show which way it moves

Answer 23

a) amplitude is the distance of a peak/trough from the rest position
wavelength is the distance between peaks/troughs

b)
c) particles move up and down

Question 24

A graph shows a wave. Each square represents 1mm.

The wave rises 4 squares before falling again.

Work out the amplitude of the wave.

Answer 24

middle = 4/2 = 2

2 mm

Question 25

compression

Answer 25

an area of increased pressure

the particles in a wave are closer together than average

Question 26

rarefaction

Answer 26

an area of reduced pressure

the particles in a wave are further apart than average

Question 27

On a wave graph of a longitudinal wave, what do the peaks and troughs also represent?

Answer 27

peaks: compression
troughs: rarefaction