waves & sound

Question 1

wave speed

Answer 1

rate at which a wave transmits the energy or matter it is carrying. v= frequency*wavelength

Question 2

angular frequency

Answer 2

radians/second

Question 3

frequency

Answer 3

1/T where T = period of the wave

Question 4

period

Answer 4

T=1/f time it takes for a wave to complete one full cycle

Question 5

traveling wave

Answer 5

have nodes and antinodes that move with wave propagation

Question 6

standing wave

Answer 6

antinodes and nodes do not move with wave propagation

Question 7

transverse wave

Answer 7

direction of particle oscillation is perpendicular to propagation - light

Question 8

longitudinal waves

Answer 8

propagate parallel to medium - sound

particles of medium vibrate/oscillate about an equilibrium position resulting in areas of compression alternating with decompression

• results in alternating regions of increased and decreased particle density

Question 9

sound

Answer 9

• requires a medium – can travel in solid, liquids, gases, but does not travel in a vacuum
• mechanical vibration

Question 10

linear density

Answer 10

• mass to length ratio of string
• u=m/L

Question 11

speed of sound

Answer 11

• also - v=sqrt(B/p) where B is equal to the bulk modulus - a measure of the medium’s resistance to compression and p =density
  
  • B increases from gas to liquid to solid being the highest
    
    • thus sound moves slowest in gases!

Question 12

pitch

Answer 12

• frequency of sound
• human hearing range = 20hz to 20,000Hz
  
  • infrasonic - less than 20 hz
  • ultrasonic - greater than 20,000Hz

Question 13

doppler effect

Answer 13

• difference between the actual frequency of a sound and its perceived frequency when the source of that sound and the sound’s detector are moving relative to one another
• if the source and detector are moving toward eachother, perceived frequency, f’, is higher than actual f
• sound waves in front of the moving object are compressed (shorter wavelength) and sound waves behind object are lengthened

Question 14

sound intensity

Answer 14

• average rate of energy transfer per area across a surface that is perpendicular to the wave
• aka power transported per unit area
• SI units = W/m²
• proportional to amplitude²
• related to distance from the source of the sound wave = I is inversely proportional to the square of the distance from the source
  
  • pwr is transmitted over larger and larger areas the farther from the source as they travel