P5.1

Question 1

What is a wave?

Answer 1

An oscillation that transfers energy

Question 2

What is the difference between transverse and longitudinal waves?

Answer 2

Longitudinal waves oscillate parallel to the source of energy, but Transverse waves oscillate perpendicular to the source of energy

Question 3

What are longitudinal waves made up of?

Answer 3

Compressions (high pressure) and rarefactions (low pressure)

Question 4

What is amplitude?

Answer 4

Distance from the middle to the top OR bottom of a wave

Question 5

What is wavelength?

Answer 5

Distance from one point on a wave to the same point on the next wave

Question 6

What is frequency?

Answer 6

The number of waves per second

Question 7

What is time period?

Answer 7

The time taken for a wave to pass a given point

Question 8

How do you work out wave velocity?

Answer 8

Wavelength x Frequency

Question 9

How do you work out Time period?

Answer 9

1 / F

Question 10

Explain/model why waves transfer energy but not matter

Answer 10

Water waves
The surface of the waves move up and down as it moves through the water.
This means the water simply bobs up and down
Can be modelled by putting a cork in the water,it wont move but waves will
Waves are oscillations that transfer energy
Another example is sound,waves move away from your mouth but air doesnt move

Question 11

How do you use a ripple tank to find out wave velocity?

Answer 11

You can find wavelength with a strobe light and a ruler
You can find frequency by counting the rotations of the motor (or counting waves if you can)
Then times them together

Question 12

Where would waves travel the fastest?

Answer 12

In a vacuum

Question 13

What property of a wave never changes?

Answer 13

Frequency

Question 14

If a wave speeds up, does it move away or towards the normal?

Answer 14

Away

Question 15

What is the normal?

Answer 15

A line at 90 degrees to the surface where a wave passes

Question 16

What 3 things can happen when a wave hits a boundary?

Answer 16

Reflected,transmitted or absorbed

Question 17

What is ultrasound?

Answer 17

A sound with a frequency higher than 20KHz

Question 18

How is ultrasound used in medical imaging?

Answer 18

A transmitter sends a beam of ultrasound waves into the patient
They reflect from different boundaries
Distances are calculated by speed / time
Those distances are used to create an image

Question 19

How do we hear sound?

Answer 19

The outer ear (pinna and auditory canal) directs waves to the ear drum,which vibrates
Making the ossicles vibrate and amplify the vibration
They pass through the oval window and through semicircular canals and to the cochlea
The cochlea converts it to electric signals and passes it onto the brain,which receives it as sound

Question 20

What is inside the cochlea

Answer 20

It is shaped like a snail shell and has fluid which transmits movements to small hairs on the wall - attached to sound detecting cells. they release chemical substances making nerves send signals to our brain through the auditory nerve

Question 21

Why can we only hear a certain frequency range of sound?

Answer 21

In our cochlea, certain hairs resonate at certain frequencies. We do not have hairs that resonate at frequencies like ultrasound meaning that we cannot hear them as they are not picked up