Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physics > 3 Waves > Flashcards

3 Waves Flashcards

1
Q

what is hertz measuring

A

the frequency of something

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the frequency of a wave

A

the amount of cycles per second

the pitch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

longitudinal waves

A

the waves oscillate in the parallel (same direction) to the direction they travel in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

transverse waves

A

the waves oscillate perpendicular (at right angles) to the direction they travel in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

examples of longitudinal waves

A

sound waves
seismic p-waves
spring/slinkie

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

examples of transverse waves

A

electromagnetic waves
ripples in the sea
mexican wave
seismic s-waves
rope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the amplitude of a wave

A

The distance from the undisturbed position to the peak or trough of a wave

the volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is the wavefront of a wave

A

the wavefront is a way of drawing a wave from above (all of the waves are drawn in the same phase, eg all troughs)

each line represents one wave and if they are close together that shows a high frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the wavelength of a wave

A

The distance from one point on the wave to the same point on the next wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the period of a wave

A

the time it takes for one wavelength to happen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what do waves transfer

A

transfer energy and information, without transferring matter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the formula with wavelength, frequency, wave speed

A

wave speed = frequency x wavelength
v=fλ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the formula with frequency and time period

A

frequency = 1 / time period
f=1/T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the doppler effect

A

the change in wavelength and frequency of a wave emitted by a moveing source

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

why does the doppler effect change the frequency of a wave

A

When the source of the wave is moving towards the observer, each successive wave cycle is emitted from a position closer to the observer than the previous cycle. As a result, the time between the arrival of each wave at the observer is reduced, which effectively increases the frequency of the wave as observed by the observer2.

Conversely, if the source of the wave is moving away from the observer, each wave cycle is emitted from a position farther from the observer than the previous cycle. This increases the time between the arrival of each wave at the observer, effectively reducing the observed frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

why does the doppler effect change the wavelength of a wave

A

When the source of the wave is moving towards the observer, each successive wave cycle is emitted from a position closer to the observer than the previous cycle1. This causes the wavefronts to “bunch up”, effectively shortening the wavelength as observed by the observer3. This is why waves appear “squeezed” or “compressed” when the source is moving towards the observer4.

Conversely, if the source of the wave is moving away from the observer, each wave cycle is emitted from a position farther from the observer than the previous cycle1. This causes the wavefronts to spread out, effectively lengthening the wavelength as observed by the observer3. This is why waves appear “stretched out” when the source is moving away from the observer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

can all waves be reflected or refracted

A

yes in the right circumstances

18
Q

what type of wave is light waves

A

transverse

19
Q

can light waves be reflected or refracted

A

yes

20
Q

what is the law of reflection

A

The law of reflection states that the angle of incidence (the angle at which the wave hits the surface) equals the angle of reflection (the angle at which the wave bounces off the surface).

21
Q

what is reflection

A

A wave hits a boundary between two media and does not pass through, but instead stays in the original medium

where angle i = r

22
Q

what is the formula with refractive index, angle of incidence, angle of refraction

A

refractive index = sin(angle of incidence) / sin(angle of refraction)
n = sin(i) / sin(r)

23
Q

practical: To investigate the refraction of light using rectangular blocks, semi-circular blocks and triangular prisms

A

Place the block on a sheet of paper, and carefully draw around the rectangular perspex block using a pencil

Switch on the ray box and direct a beam of light at the side face of the block
Mark on the paper:
- A point on the ray close to the ray box
- The point where the ray enters the block
- The point where the ray exits the block
- A point on the exit light ray which is a distance of about 5 cm away from the block

Draw a dashed line normal (at right angles) to the outline of the block where the points are

Remove the block and join the points marked with three straight lines

Replace the block within its outline and repeat the above process for a ray striking the block at a different angle

Repeat the procedure for each shape of perspex block (prism and semi-circular)

24
Q

practical: investigate the refractive index of glass using a glass block

A

Place the glass block on a sheet of paper, and carefully draw around the rectangular perspex block using a pencil

Switch on the ray box and direct a beam of light at the side face of the block
Mark on the paper:
- A point on the ray close to the ray box
- The point where the ray enters the block
- The point where the ray exits the block
- A point on the exit light ray which is a distance of about 5 cm away from the block

Draw a dashed line normal (at right angles) to the outline of the block where the points are

Remove the block and join the points marked with three straight lines

Replace the block within its outline and repeat the above process for a ray striking the block at a different angle

25
Q

what is total internal reflection

A

Total Internal Reflection (TIR) is a phenomenon in physics where waves, such as light waves, arriving at the boundary or interface from one medium to another (e.g., from water to air) are not refracted into the second (“external”) medium, but completely reflected back into the first (“internal”) medium

26
Q

when does total internal reflection happen

A

The angle of incidence is greater than the critical angle and the incident material is denser than the second material

27
Q

what are the conditions needed for total internal reflection

A

The angle of incidence > the critical angle
higher refractive index than air
when a ray tries to go from a denser to a less dense material

28
Q

how is total internal reflection used in optical fibres

A

they are made of glass or plastic with in outer cladding which has a lower refractive index than the glass
which means that the light will always hit a boundary at a higher value than the critical angle

the light waves are totally internal reflected down whole wire meaning all of the wave reaches the other end which allows all of the information to to be passed through the fibre without any being lost

29
Q

what is the critical angle

A

The critical angle is a concept in physics that describes the angle of incidence at which light (or any wave) refracting from a denser medium to a less dense medium is refracted along the boundary between the two media, without crossing it

As the angle of incidence is increased, the angle of refraction also increases until it gets closer to 90°
When the angle of refraction is exactly 90° the light is refracted along the boundary
At this point, the angle of incidence is known as the critical angle c

30
Q

what is the formula with critical angle and refractive index

A

sin(critical angle) = 1 / refractive index
sin(c)=1/n

31
Q

what type of wave is a sound wave

A

longitudinal waves

32
Q

can sound waves be reflected and refracted

A

yes

33
Q

what is the frequency range of human hearing

A

20Hz - 20,000Hz

34
Q

practical: investigate the speed of sound in air

A

Connect two microphones to an oscilloscope

Place them about 2 m apart using a tape measure to measure the distance between them

Set up the oscilloscope so that it triggers when the first microphone detects a sound, and adjust the time base so that the sound arriving at both microphones can be seen on the screen

Make a large clap using the two wooden blocks next to the first microphone

Use the oscilloscope to determine the time at which the clap reaches each microphone and the time difference between them

Repeat this experiment for several distances, e.g. 2 m, 2.5 m, 3 m, 3.5 m

speed = distance / time

35
Q

how can a oscilloscope and microphone be used to display a sound wave

A

Microphone Connection: A microphone is connected to an oscilloscope. The microphone captures sound waves and converts them into electrical signals
Signal Conversion: The oscilloscope takes these electrical signals and converts them into a visual representation, displaying them as waveforms on its screen

36
Q

practical: investigate the frequency of a sound wave using an oscilloscope

A

Connect the microphone to the oscilloscope

Test the microphone displays a signal by humming

Adjust the time base of the oscilloscope until the signal fits on the screen - ensure that multiple complete waves can be seen

Strike the tuning fork on the edge of a hard surface to generate sound waves of a pure frequency

Hold the tuning fork near to the microphone and observe the sound wave on the oscilloscope screen

Freeze the image on the oscilloscope screen, or take a picture of it

Measure the number of squares for one complete cycle

multiply the number of squares by the time base to find the time period

frequency = 1/T

37
Q

how does the pitch of a sound relate to the frequency of vibration

A

the higher the pitch of a sound, the higher frequency the wave has

38
Q

how does the volume of a sound relate to the amplitude of vibration

A

the higher the amplitude of a wave, the louder the sound is

39
Q

what happens to a wave if it enters a more dense material at an angle

A

it will bend towards the normal

40
Q

what happens to a wave if it enters a less dense material at an angle

A

it will bend away from the normal

Physics (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions