Physics 101 Test #2 Ball State
the speed of sound increases _________m/s for each degree C the air temp increases
.6 m/s
What approximate open tube length will resonate best with a sound wave having a wavelength of 0.30 m? a. 0.075 m b) 0.15 m c) 0.30 m d) 0.60 m e) 1.20 m
0.60 m
what is the range of decibels we can hear?
10-120 whispering---jet plane take off
1st harmonics L=
1st L= wavelength/2 2nd L= wavelength
Audiospectrum
20 Hz- 20,000 Hz
At dry air temp the speed of sound is
331.5 m/s at 0 degrees C
What is a wave?
A disturbance that carries energy from place to place
What is a electromagnetic wave?
A wave that does not need a medium to travel through. Ex: Light waves
What is a mechanical wave?
A wave that needs medium to travel through Ex: sounds needs to travel through air
In Phase
Amplitude that is the sum of both crest and crest meeting together (constructive) (greater amplitude)
Refraction
Bending of a wave as it passes obliquely from one medium to another of different propagation speed
Cyan is a mixture of _____ and _____
Blue and green light
Doppler Effect
Change in f due to relative motion of the wave source and the observer (Siren sounds louder as it approaches but the volume is not changing; you are receiving a different frequency)
Out Phase
Crest does not meet crest (disruptive) partially or completely cancel each other out so amp= 0 or minimum
T or F Sound waves do not bend when they travel into a different medium
F
T or F The speed of sound in air is faster than in gas
F
T of F Sound waves are transverse waves
F- Longitudinal
T or F Sounds do not possess the characteristics that are common to all other waves
F- They do
T or F Sound waves can travel in a vacuum
F- they cannot travel in a vacuum
T or F Frequency below 20 HZ are ultrasonic
F-Infrasonic
Harmonics
Frequencies that are integral multiples of fundamental frequencies
What is the unit for frequency?
Hertz
Sounds speed depends on the ________ of air
temperature
Reverberation is
the prolonging of sound by reflection (several from different distances) Ex: thunder
Time Period is?
the time taken by one wave vibration T=1/f f=1/T
Interference
two waves propagating may superimpose or overlap each other when they propagate through the same place at the same time
If the wavelength of the light is 800 nm and the speed of light is 3.00 x 10^8 m/s, what is the frequency of the light?
wavelength = 800 nm = 800 * 10 ^-9 m V = f f = (v / ) = (3.00 x 10^8 / 800 * 10^ -9) = 3075 *10 ^14 HZ
A closed end pipe resonates when
wavelength= 4(L+0.4d)
The complimentary color of blue is______________
yellow
Antinodes
Place of maximum vibration
Nodes
Place of no vibrations
What color is transmitted by a piece of red glass?
Red
The speed of sound is fastest in what medium?
Solid, then liquid, then gas
Ultrasonic
Sound above 20,000 Hz
Infrasonic
Sound below 20 Hz
What is Velocity?
Speed of the wave V= lambda * f
Standing waves
Standing wave, also called stationary wave, combination of two waves moving in opposite directions, each having the same amplitude and frequency. The phenomenon is the result of interference—that is, when waves are superimposed, their energies are either added together or cancelled out.
T or F Echoes are an example of reflection of sound waves
T
T or F Sound is mechanical wave
T
T or F The audible range of sound in 20 HZ- 20,000 HZ
T
T or F The human ear relates amplitude to loudness
T
T or F The speed of sound in solid is faster than the speed of sound in gas
T
T or F Sounds possess the properties that are common to all waves
T
T or F The human ear relates pitch to frequency
T
Amplitude is
The maximum displacement Transversal: Maximum height of the wave Longitudinal: mean position to the start
What is a transverse wave?
The medium moves at a 90 degree angle to the direction of the wave. Up and down. Crest and trough.
Frequency is
The number of complete vibrations per unit (Hz)
Fixed end Termination
The reflected wave is inverted wen it reflects from a more dense medium
Free end Termination
The reflected wave is upright when it reflects from a less dense medium (loose and soft boundary)
Echoes are
The reflection of sound when the wave changes medium or hits a boundary
Diffraction
The spreading of a wave around a barrier or through and opening
when light goes into water some is partially reflected, the rest is _________
Transmitted
Wavelength (Lambda) is?
Transverse: crest to the next crest (or T to T) Longitudinal: compression to compression (or R to R)
A sound wave moving through water has a frequency of 256 Hz and a wavelength of 5.77m. What is the speed of the wave?
V = f = 5.77 * 256 = 1477.12 m/s
If the wavelength of the light is 500 nm and the speed of light is 3.00 x 10^8 m/s, what is the frequency of the light?
V = f wavelength f = (v / wavelength ) = (3.00 x 10^8 / 500 * 10^ -9) = 6 * 10^14 HZ
If the speed of light is 3.00 x 10^8 m/s and has a frequency of 215 Hz, then what is the wavelength of light?
V = f wavelength = (v / f) = (3.00 x 10^8 / 215) = 1.4 * 10 ^ 6 m
If the speed of light is 3.00 x 10^8 m/s and has a frequency of 512 Hz, then what is its wavelength?
V = f wavelength = (v / f) = (3.00 x 10^8 / 512) = 5.9* 10 ^5 m
1A sound wave moving through water has a frequency of 343 Hz and a wavelength of 1.73m. What is the speed of the wave?
V = wavelength f = 1.73 * 343 = 593.4 m/s
What is the velocity of light?
V of light= C= 3* 10^8 m/s
What color of light has the greatest frequency in a vacuum?
Violet
Amplitude is
Volume
An open end pipe resonates when
Wavelength= 2 (L+0.8d)
Reflection
When the wave hits a boundary and comes back The angle of reflection = The angle of incidence All rays meet at the same point on the plane
Constructive Interference
When the wave match each other when propagating Ex: ~ ~ C1=C2 T1=T2 Amplitude increases; Displacement is max
Disruptive Interference (or Partial Disruptive)
When the waves do not line up after interference Ex: C1=T2 and T1=C2 Displacement and Amp. will be less than the individual waves
Vector Sum (Principle of Superimposition (Interference))
Y=Y1+Y2 Troughs= (-) Crests= (+) Ex: Constructive= +2+ +2= 4 Displacement Ex: Disruptive= +2+ -2= 0 Displacement
Do all wave have the same properties and characteristics?
Yes
What approximate closed tube length will resonate best with a sound that has a wavelength of 0.30 m? a. 0.075 m b) 0.15 m c) 0.30 m d) 0.60 m e)1.20 m
a) 0.075 m
If the frequency of a certain wave is 10 hertz, its period is a. 0.1 second. b. 10 seconds. c. 100 seconds. d. None of the above choices are correct.
a. 0.1 second
An object that completes 10 vibrations in 20 seconds has a frequency of a. 0.5 hertz. b. 2 hertz. c. 10 hertz. d. 20 hertz. e. 200 hertz.
a. 0.5 Hertz
A sound wave resonates best in a closed tube when the tube length is approximately __________ of a wavelength long. a.1/4 b) 2/4 c) 3/4 d) 4/4 e) need more information
a. 1/4
Pane mirror images are _________________ virtual a. always b. sometimes c. never
a. always
Like a transverse wave, a longitudinal wave has a. amplitude, frequency, wavelength, and speed. b. amplitude, frequency, and wavelength. c. amplitude, wavelength, and speed. d. wavelength, speed, and frequency. e. amplitude, frequency, and speed.
a. amplitude, frequency, wavelength, and speed.
Real images produced by mirrors a. are always located in front of the mirror. b. are always located behind the mirror. c. may be located in front or behind the mirror.
a. are always located in front of the mirror
As the wavelength of a wave in a uniform medium increases, its frequency will a. decrease. b. increase. c. remain the same.
a. decrease
As the frequency of a wave increases, the period of the wave a. decreases. b. increases. c. remains the same
a. decreases
In a longitudinal wave, the particles of the medium vibrate or move _________________ to the direction the wave is traveling. a. parallel b. perpendicular
a. parallel
The change of direction of a wave as it obliquely enters a new medium and changes speed is known as a. refraction. b. diffraction. c. interference. d. reflection.
a. refraction
A sound wave resonates best in an open tube when the tube length is approximately ____ of a wavelength long. a) 1/4 b) 2/4 c) 3/4 d) 4/4 e) need more information
b. 2/4
If you double the frequency of a vibrating object, its period a. doubles. b. halves. c. is quartered.
b. Halves
Virtual images produced by mirrors a. are always located in front of the mirror. b. are always located behind the mirror. c. may be located in front or behind the mirror.
b. are always located behind the mirror
The spreading of a wave around a barrier or through an opening is known as a. refraction. b. diffraction. c. interference. d. reflection.
b. diffraction
In a transverse wave, the particles of the medium vibrate or move _________________ to the direction the wave is traveling. a. parallel b. perpendicular
b. perpendicular
The yellow clothes of a stage performer can be made to look black when illuminated by only ___________ light
blue
The string is 6.0 meters long and is vibrating as the third harmonic (three loops). The string vibrates up and down with 45 complete vibrational cycles in 10 seconds. Determine the wavelength for this wave. a. 2 m b. 3m c. 4 m d. 6 m e. 12 m
c. 4m
The result of the superposition of two or more waves traveling through the same medium is known as a. refraction. b. diffraction. c. interference. d. reflection.
c. Interference
Plane mirror images are ___________ reduced a. always b. sometimes c. never
c. never
Plane mirror images are _____________ enlarged. a. always b. sometimes c. never
c. never
An opaque object is green when illuminated with white light. What color is it when viewed through a blue transparency?
cyan
What approximate wavelength of sound resonates best with an open tube that is 0.40 m long? a. 0.10 m b) 0.20 m c) 0.40 m d) 0.80 m e) 1.60 m
d) 0.80 m
A wave travels an average distance of 6 meters in one second. What is the wave's velocity? a. less than 0.2 m/s b. 1 m/s c. 3 m/s d. 6 m/s e. more than 6 m/s
d. 6 m/s
The turning back of a wave as it reaches the boundary of the medium through which it is traveling is known as a. refraction. b. diffraction. c. interference. d. reflection.
d. reflection
What approximate wavelength of sound resonates best with a closed tube that is 0.40 m long? a. 0.10 m b) 0.20 m c) 0.40 m d) 0.80 m e) 1.60 m
e. 1.60 m
Frequency is
pitch
The 1st harmonics wavelength=
L2
Harmonic length equation
L= N * wavelength/ 2
Sound waves
Longitudinal and mechanical
What is a longitudinal wave?
Medium moves back and forth in the same direction as the wave. Compassion and refraction.
Do vacuums have sound?
No
Does a wave carry matter with it?
No, just energy
