Test

1) All sounds are produced by:	a) sound waves b) vibrations c) resonances d) rarefactions
2) Vibrating sources send a disturbance through the air in the form of:	a) longitudinal waves b) latidunal waves c) pulses d) vibrations
3) A pulse of compressed air is called a:	a) rarefaction b) vibration c) condensation d) none of the above
4) The human ear can normally hear between:	a) 10 and 10,000 hertz b) 5 and 5,000 hertz c) 20 and 20,000 hertz d) 30 and 30,000 hertz
5) Sounds travel through:	a) the air b) liquids c) solids d) all of the above
6) Increased temperatures and the amount of water vapor in the air decreases the speed of sound.	a) True b) False
7) Sound cannot travel through a vacuum.	a) True b) False
8) The speed of sound in a material depends on the elasticity of the material.	a) True b) False
9) Natural frequency is the maximum energy required to produce forced vibration.	a) True b) False
10) If crests of one wave overlap the crests of another wave, there is an increase in amplitude.	a) True b) False

Label the crest, trough, amplitude, and wavelength

The speed of sound in air is approximately v = 331 m/s + T (0.61 m/s/0C), where T is the temperature in degrees, Celsius, not the period. Use this to calculate the the velocity of a sound wave at a temperature of 50⁰ C