P5.1

Question 1

What is a wave

Answer 1

A wave is an oscillation that transfers energy.

Question 2

What are mechanical waves

Answer 2

Mechanical waves such as sound and water waves need a (matter) medium to travel through whereas electromagnetic waves don’t.

Question 3

What is longitudinal wave

Answer 3

The direction of the travel of the wave is the same as the direction of vibration of air molecules

Question 4

What is a transverse wave

Answer 4

Transverse waves the direction of the vibrations are at right angles to the direction of the wave travel (water waves). The energy transfer is in the direction of the wave

Question 5

What is amplitude

Answer 5

Distance from the middle to the top or bottom of wave

Question 6

What is wavelength

Answer 6

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

Question 7

What is frequency

Answer 7

Number of waves or oscillations per second (Hz)

Question 8

What is time period

Answer 8

Time for a wave to pass a given point

Question 9

What does a time trace show

Answer 9

It shows how displacement varies with time at a particular position.

Question 10

A snapshot

Answer 10

A snapshot shows how displacement varies with distance

Question 11

What is the formula for wave velocity

Answer 11

Wave velocity = frequency x wave length

Question 12

Frequency formula

Answer 12

1/t

Question 13

How can you measure wave velocity

Answer 13

You can measure the velocity of a wave ripple tank. You can measure the wavelength using a ruler and flashing strobe and calculating the number of rotations per minute for the frequency. You then put it in the formula to work out wave speed.

Question 14

Another way to measure wave velocity

Answer 14

Echoes

Question 15

Last way to measure wave velocity

Answer 15

You can also connect a pair of microphones a certain distance apart to an oscilloscope.

Question 16

What happens when a wave travels to one medium from another

Answer 16

Its velocity can change and so can its direction. This is refraction.

Question 17

When a sound wave becomes quicker what happens

Answer 17

The direction of the sound wave moves away from the line at 90 degrees to the surface called the normal.

Question 18

When a sound wave speeds up what happens

Answer 18

It’s frequency stays the same, the wave speed increases the wave length increases

Question 19

What happens when a sound wave meets a boundary

Answer 19

Be reflected
Be transmitted
Be absorbed

Question 20

What is ultrasound

Answer 20

Ultrasound is a sound with a frequency greater than 20,000. And it can be focused into a beam.

Question 21

What is ultrasound used for

Answer 21

Ultrasound is used to image soft tissue.
The transmitter beams ultrasound into the mother. The waves can reflect of the different boundaries. The machine calculates the distances using time and velocity and uses those distances to produce an image. You can use this to find depths.

Question 22

What can u use to work out depth

Answer 22

You can use echoes and sonar to calculate depths

Question 23

What happens when sound hits a solid

Answer 23

When a sound hits a solid some a solid particles vibrate and the wall gets a bit hotter

Question 24

What is your ear designed to do

Answer 24

Your ear is designed to detect, amplify and convert sound to an electrical signal

Question 25

What does the outer ear do

Answer 25

The outer ear (pinna and auditory canal) gathers the sound wave and directs it to the eardrum which vibrates.

Question 26

What does the eardrum do

Answer 26

As the ear drum vibrates it makes the ossicle vibrate which amplify the vibration and pass it on to the inner ear through the oval window.

Question 27

What does the cochlea do

Answer 27

The cochlea is shaped like a snail shell and contains fluid which transmits the movement of the oval window to small hairs on the inside wall of the cochlea. It then sends a signal to the auditory nerves to your brain.

Question 28

What is a natural frequency

Answer 28

If you apply a vibration to them at their natural frequency they will vibrate with a very big amplitude.

Question 29

What do the hairs inside the cochlea do

Answer 29

Vibrate at different frquencies. The range of frequencies that you can hear depends on the range of lengths of hair in your year.

Question 30

What happens as you get older

Answer 30

As you get older your loose your short hairs. Leading to increased difficulty to hear high frequency sounds.

Question 31

Frequency formula

Answer 31

frequency = waves/time