P5.1

Question 1

Vibrations

Answer 1

Back and forth motion, when something is displaced from its’ equilibrium position

Question 2

Sound waves

Answer 2

A wave produced by a vibration. REQUIRES A MEDIUM IN ORDER TO TRAVEL

Question 3

Do electromagnetic waves need a medium?

Answer 3

NO

Question 4

Longitudinal waves

Answer 4

When the direction of vibration is parallel to the direction of energy transfer

Question 5

Transverse waves

Answer 5

When the direction of vibration is PERPENDICULAR to the direction of energy transfer

Question 6

Amplitude

Answer 6

Distance from the peak/trough to the principle axis/normal line

Question 7

Wavelength

Answer 7

Distance from one peak/trough to the next

Question 8

Frequency

Answer 8

Number of oscillations/peaks passing through a point in one second

Question 9

Time period

Answer 9

Time for one wave to pass a given point

Question 10

Which part of a wave diagram represents HIGH PRESSURE?

Answer 10

Peak

Question 11

Which part of a wave diagram represents LOW PRESSURE?

Answer 11

Trough

Question 12

Wave velocity

Answer 12

The speed at which the energy of a wave is transferred

Question 13

Unit for time period

Answer 13

Seconds, s

Question 14

Time period equation

Answer 14

1 / frequency

Question 15

Wave equation

Answer 15

Wave speed (m/s) = frequency (Hz) x wavelength (m)

Question 16

Wave compression

Answer 16

High pressure- particles squashed together

Question 17

Wave rarefaction

Answer 17

Low pressure - particles spread far apart

Question 18

How can one physically model waves?

Answer 18

Using ripples in water ONLY FOR TRANSVERSE WAVES

Question 19

How to measure the velocity of ripple in water?

Answer 19

Using a ripple tank, u already know the frequency at which the machine is making them.

Calculate wavelength by using a strobe (flashing light) and a ruler

Question 20

How to Measure velocity of sound waves?

Answer 20

OSCILLOSCOPE - device that shows a changing P.D

Uses same idea of how microphones work

Question 21

2 facteors affecting velocity of a sound wave

Answer 21

Temperature

Pressure

Question 22

Refraction

Answer 22

Change in wave direction when the speed changes whilst going from one medium to another

Question 23

Does the frequency of a wave ever change?

Answer 23

NO, THE FREQUENCY OF EACH WAVE IS UNIQUE AND CONSTANT.

It helps to identify the wave, so if the frequency changes, then the wave will not be the same

Question 24

3 possibilities when a wave hits a boundary

Answer 24

• reflects (e.g. echo)
• transmitted
• absorbed

IT DEPENDS ON THE DENSITIES OF THE REGION ON EITHER SIDE OF THE BOUNDARY

Question 25

Frequency of ultrasound

Answer 25

Greater than 20,000 Hz - hence we can’t hear it, beyond human ear range

Question 26

How does ultrasound produce images of a baby?

Answer 26

- ultrasound beam is sent into mother - waves reflect off the different boundaries of the baby - machine calculates distance, using time taken and velocity of the wave and uses the distances to produce an image.

Question 27

What does the outer ear (pinna and auditory canal) do ?

Answer 27

Gather the sound waves and directs it to the ear drum ,which then vibrates

Question 28

What does the vibration of the ear drum cause?

Answer 28

It causes the ossicles to vibrate. These amplify the vibration and pass it to the inner ear through the oval window

Question 29

Where does the oval window lead to?

Answer 29

The cochlea. It is a snail shell shape and is filled w/ liquid - transmits the movement of the oval window to the small hairs on the inside wall of the cochlea - hairs are attached to sound detecting cells that release chemical substances when stimulated - makes nerves send a signal down the auditory canal to the brain - brain processes the signal and you hear the sound.

Question 30

Resonance

Answer 30

The large amplitude oscillation that happens when u make something vibrate @ its’ natural frequency

Question 31

Natural frequency

Answer 31

The frequency at which an object vibrates/oscillates if it is displaced (E.g. for humans it is 20Hz to 20,000Hz - the parts of the ear cannot vibrate slower or faster than this)