Combined Physics - P6 Waves Flashcards
What two types of wave are there?
- Transverse
- Longitudinal
Give an example of a longitudinal wave
Sound
Describe how longitudinal waves transfer energy.
Vibrations are parallel to energy transfer
Give an example of a transverse wave
- All electromagnetic waves
- A ripple on water
- A wave on a string
Describe how transverse waves transfer energy.
Vibrations are perpendicular to energy transfer
Compare the sound of the two waves in the image in terms of loudness and pitch.
- They have the same loudness.
- Wave B has a higher pitch.
Name the properties of the wave labelled a) and b)
a) Wavelength
b) Amplitude
Name the two regions of a longitudinal wave labelled ‘C’ and ‘R’.
C = compression
R = rarefaction
What equation links wave speed, frequency and wavelength?
Wave speed = frequency x wavelength
V = 𝘧 λ
What are X-rays used for?
Medical imaging
What EM waves can our eyes detect?
Visible light
What are gamma rays used for?
- Killing cancer cells
- Sterilizing medical equipment
What does frequency mean?
The number of complete waves passing a certain point in a second (1 Hz is 1 wave per second)
What EM waves can have hazardous effects on human body?
Ultraviolet waves, X-rays and gamma rays
Which EM wave causes skin cancer?
Ultraviolet waves cause skin cancer
Write the electromagnetic spectrum in order from longest to shortest wavelength.
Compare the sound of the two waves in the image in terms of loudness and pitch.
- They have the same pitch.
- Wave B is quieter than Wave A.
Name the EM wave that communicates with satellites
Microwaves
What danger do X-rays and gamma rays pose?
Can cause cancer
What are microwaves used for?
- Satellite communications
- Cooking food
- Mobile phone communication
What is visible light used for?
1) Communication using fibre optics
2) Anything that you need to see e.g.:
- Charging lights on battery chargers
- Traffic Lights
- Lights on displays such as TV, phone, laptop
What are radio waves used for?
Television and radio
What are infrared waves used for?
- Electrical heaters
- Cooking food
- Infrared cameras
- TV remotes
What is ultraviolet used for?
- Tanning beds
- Detecting forged bank notes
What is the dashed line in a refraction diagram called?
Normal
What do you call the process whereby light bends as it enters a different medium?
Refraction
Higher Q. What can oscillations in electrical circuits cause?
Radio waves
Why does light bend as it moves from air into glass?
Glass is denser than air, so the light wave slows down.
Higher Q. How can radio waves themselves induce oscillations in an electrical circuit?
Radio waves can be absorbed, creating an alternating current with the same frequency as the radio wave itself.
Describe how you would use a ripple tank to measure the speed of a water wave.
- Set the frequency of the wave on the signal generator.
- The dipper will oscillate and generate a wave at the set frequency.
- Turn the strobe light on.
- Take a picture of the wave fronts that appear on the screen.
- Using a ruler, measure the wavelength of one wave (to increase accuracy, measure the length of 10 waves then divide by 10).
- Use the equation: v=fλ to calculate the speed of the wave.
Describe how you would measure the speed of a wave on the string?
- Set the frequency of the wave on the signal generator.
- Using a ruler, measure the wavelength of one wave (to increase accuracy, measure the length of 10 waves then divide by 10).
- Use the equation: v=fλ to calculate the speed of the wave.
Put the following surfaces in order of the amount of infrared radiation they emit (from most to least).
Shiny Black, Matt Black, Silver, White
- Matt black (most)
- Shiny black
- White
- Silver (least)
Higher Q. Complete the diagram to show waves moving from a less dense to a more dense medium.
Higher Q. Complete the diagram to show waves moving from a less dense to a more dense medium.
Describe how you would investigate the amount of infrared radiation emitted by different surfaces using the equipment below.
- Fill the Leslie’s cube with boiling water and place on a heat proof mat.
- Measure 15 cm from the cube using a ruler and place an infrared detector there facing the cube.
- Record the amount of infrared it detects.
- Repeat for each side of the cube (which has different faces, e.g. silver, black matt, black shiny, white).
Describe how the equipment can be used to measure the speed of sound
- Connect a speaker to a signal generator and switch on to a set frequency (this gives your frequency, f)
- Connect microphones to the oscilloscope so they each show a wave on the screen.
- Place both microphones next to the oscilloscope.
- Move one microscope away until the waves on the screen match each other.
- Measure the distance between the microphones at this point – this is the wavelength, λ.
- Use the equation: v=fλ to calculate the speed of the wave.
