Waves Flashcards
How do you measure the wavelength
The distance between two peaks
How do you measure amplitude
The maximum displacement of the wave from the centreline (the peak to the centreline)
What is Hz used to measure
Frequency
What is the difference between transverse and longitudinal waves
Transverse has perpendicular direction of energy transfer and movement of particles, whereas Longitudinal has paraLLeL
What do waves transfer and what do they not transfer
They transfer energy and information, but NOT matter
What is the equation for wave speed
Wave speed = frequency x wavelength
v = f λ
What is the relationship between frequency and time period
Frequency = 1/time period
What is the wavefront
A line connecting the peaks of waves, but across the tops of waves that are next to each other. Imagine a 3D view of a wave, then imagine many waves just like that one next to it. The wavefront is the line that connects the peaks. See camera roll 24th October for diagram (ignore the peter crouch picture - i hope by now he has a really good evo that i put him into)
What is the period of a wave
The time taken for one complete wave to pass a point
What is frequency
How often a peak is recorded
What is a rarefaction
An area where the frequency is lower than normal in a longitudinal wave
What is an area of compression on a longitudinal wave
An area where the frequency is higher than normal
What is the wavelength of a longitudinal wave
The distance between two consecutive rarefactions/compressions
What are peaks and troughs comparable to in longitudinal waves
The distance between the midpoint between two compressions and the nearest compression
What is the range for human hearing
20 Hz - 20,000 Hz
What does the pitch of a sound depend on
The frequency of the vibration of the sound
Describe an experiment for measuring the speed of sound in air
Required equipment: 2 people, a trundle wheel/tape measure and a stopwatch
1. Get 2 people
2. Stand far away from each other
3. Get one person to clap, the other uses a stopwatch to record the time between the person clapping and the second person hearing the sound
4. Repeat this 5 times for accuracy
5. Average out the time
6. Measure the distance between the people using a tape measure or trundle wheel
7. Using the equation speed = distance/time, calculate the speed of sound to be around 340m/s
What does the loudness of a sound depend on
The amplitude
Fill in the blank: a large sound has a large _______
Fill in the blank: a high pitched sound has a _______ frequency
High
Fill in the blank: a high pitched sound has a high ______
Frequency
How can an oscilloscope and microphone be used to display a sound wave
A microphone converts sound energy into electrical energy in the form of electronic signals. A computer or an oscilloscope can be used to display these electronic signals, which show the same changes in amplitude and frequency as the sound waves.
How to read data from an oscilloscope
Time period: the distance between two peaks is the time period (NOT THE WAVELENGTH). For example if each square is representing 1 millisecond and the distance between the two peaks is 4 squares, then the time period of the inputted sound wave is 4 milliseconds. This can then be used to find frequency ( f = 1/T)
Amplitude: measure the distance of the peak from the rest point (centreline) THEN YOU MUST look at how many volts are per each square, then multiply that number by the distance of the peak from the rest point, to get the amplitude of the inputted sound. E.g. if distance of peak from rest point = 4cm and volts per square = 6, amplitude = 24
What is sound below 20Hz called
Infrasound
What is sound above 20,000 Hz called
Ultrasound
How are sound waves used for pregnant mothers
They can scan pre-natal babies to show size, position, heartbeat and organ development.
