Sound Flashcards
How does sound propogate?
Through longitudinal waves
FYI
What is the speed of sound in air?
Around 330m/s
Formula for distance travelled by sound?
d = vt
What is the audible frequency range for humans?
20Hz - 20kHz
True or False?
Ultrasound frequency range is 1Hz - 20Hz
False
That’s infrasound. Ultrasound is >20kHz.
Speed of sound in different media?
Fastest - in solids
Slowest - in gases
What does amplitude of a sound wave refer to?
The loudness of the sound
Apparatus used to make accurate measurements of period and amplitudein a wave?
Cathode-ray oscilloscope
Take note of the time base knob for each question
True or False?
A higher pitch sound means that the sound wave travels faster.
False
All sound waves travel at the same speed in the same medium
When frequency increases (octave), wavelength decreases.
True or False?
Sound travels in vacuum.
False
Sound needs a medium to travel
What are the factors affecting speed of sound in air?
Wind, temperature, humidity, medium, motion of air molecules
What is a compression?
A region of higher air pressure
What is a rarefaction?
A region of lower air pressure
How is sound produced from a tuning fork?
- when air molecules are pushed close to each other, a region of compression is formed
- when the air molecules are pulled apart, a region of rarefaction is formed
- a series of compressions and rarefactions are formed.
How to read a snapshot graph for sound?
- crest of the graph is centre of compression
- trough of graph is centre of rarefaction
To know the position of a particle a few seconds later, draw the same graph few seconds later and compare the positions
