Waves, Sound and Light - Topic 1, Waves Flashcards
Why is it that a circular wave produced on a tilted ripple tank forms an oval shape and not a perfect circle?
As the ripple tank is tilted, more water is on one side than the other, meaning that one side is deeper than the other. This means that the waves on one side will travel faster than those on the other side, forming an irregular circle.
What is the human range of hearing?
Human beings hear only sounds with frequencies from about 20 Hz to 20,000 Hz, although the upper limit decreases with age.
Are sound waves longitudinal or transverse waves?
Longitudinal
What produces sound?
Vibrations
Definition of an echo
If the reflecting surface is nearer than 15m, the echo joins up with the original sound which then seems to be prolonged. This is called reverberation.
What are ultrasonic waves?
Sound waves with frequencies above 20 KHz are called ultrasound waves
What is the speed of sound in air?
330 m/s
What is the speed of sound in water?
1400 m/s
What is the speed of sound in concrete?
5,000 KHz
What is the speed of sound in steel?
6000 m/s
Name some of the applications of echoes in industry
Ships use ultrasonic waves to measure the depth of the sea and to detect shoals of fish
In industry ultrasonic waves are used to reveal flaws in welded joints
Reverberation is desirable in a concert hall to stop it sounding ‘dead’, but too much causes confusion. Modern concert halls are designed for the optimum amount of reverberation. Seats and some wall surfaces are covered with sound-absorbing material.
What properties of sound suggest it as a wave motion?
Waves can be reflected, and so can sound to form an echo.
What is a transverse wave?
A progressive transverse wave is an oscillation that travels at a right angle to wave propagation
What is a longitudinal wave?
A longitudinal wave is an oscillation that travels parallel to the direction of wave propagation
What is a progressive wave?
A progressive wave is a mechanical wave motion that requires a medium or matter for the oscillations/vibrations to travel through
List the features of a progressive wave
A progressive wave can be reflected, refracted and diffracted, and requires a medium to travel through
What is the frequency of a wave?
The frequency (f) is the number of complete oscillations made in one second by a particle in the wave train
What factors affect the speed of the wave?
Medium
Frequency
Wavelength
f = Number of complete waves per second lambda = Wavelength of waves
Therefore, fxw = …
Distance moved by wave train in 1 second
Otherwise known as speed (m/s)
Amplitude definition
The amplitude (a) is the height of a crest or depth of a trough measured from the undisturbed position of what is carrying the wave
Recall the echo principle formula
V = 2nd/t
