Waves Physics

If a guitar string has a fundamental frequency of 500 Hz, what is the frequency of its second harmonic?

1000 Hz

A 3.0 m long stretched string is fixed at both ends. If standing waves with a wavelength of two-thirds L are produced on this string, how many nodes will be formed?

2

The wavelength of a fundamental frequency of a vibrating string of length L is...

2L

How many beats per second are heard when two vibrating tuning forks having frequencies of 342 Hz and 345 Hz are held side by side?

3 Hz

A 2.0 m long stretched rope is fixed at both ends. Which wavelength would not produce standing waves on this rope?

4.0 m

when a mechanical wave's amplitude is tripled, the energy the wave carries in a given time interval is increased by a factor of...

9

What is a transverse wave?

A moving wave that move or swing back and forth at a regular speed occurring perpendicular to the direction of energy transfer.

What is the difference between a pulse wave and a periodic wave?

A pulse wave is a disturbance that moves through a medium. A periodic wave is a periodic disturbance that moves through a medium.

What is a reflected pulse/ray?

A ray of light or other form of radiant energy which is thrown back from a nonpermeable or nonabsorbing surface; the ray which strikes the surface before reflection is the incident ray.

A boat produces a wave as it passes an aluminum can floating in a lake. Explain why the can is not moved along in the direction of wave motion.

As a wave travels through water, the particles travel in clockwise circles leaving the can in place.

Why does a clear stream always appear to be shallower than it actually is?

Because the clear water allows light to pass through it better, thus creating a magnifying glass effect.

What color would a red ball appear if placed under a green light?

Black because a red object only reflects red light. When a green light shines on a red object, the red ball cannot reflect therefore it appears black.

Transmitted pulse/ray

Corresponds to a given incident ray representing the light that is transmitted through the surface.

In an old fashioned pendulum clock, the bob is moved up and down to adjust the clock to keep accurate time. How would you adjust the bob in order to correct the clock that runs too fast? Explain why the adjustment works.

Decrease the pendulum and length because the period of a pendulum is proportional to the square roots of the length of the pendulum.

How are mechanical waves different from electromagnetic waves?

Electromagnetic waves can travel through space or a medium while mechanical waves need matter to transfer energy.

True or False? Waves arriving at a fixed boundary are neither reflected nor inverted.

False. they are reflected and inverted.

A convex mirror forms an image form a real object. Can the image ever be larger than the object?

For a convex mirror, there can only ever be one type of image. The image is always upright, virtual and diminished. Convex mirrors cannot create an image that is larger than the object.

What is Snell's Law?

Formula used to describe the relationship between the angles of incidence and refraction, referring to light or other waves passing though a boundary between two different isotropic media (water/glass).

Resonance

Occurs when a system is able to store and easily transfer energy between two or more different storage modes (kinetic and potential energy in the case of a pendulum)

Suppose you play a music CD in a room when there is a piano. During the silence between songs, you hear a musical note coming from the piano, but no one has touched the piano. Explain your observation.

One of the musical sounds from the CD matches the natural frequency of the string in the piano. As a result, the energy of the sound wave causes the string to vibrate in resonance with a note from the CD.

What color would a red ball appear to be if placed under a red light?

Red because since the object is red it reflects the red spectrum of light, therefore under red light, the object is red.

What is a ball bouncing on the floor an example of?

Simple Harmonic Motion

Give three examples of mechanical waves.

Sound Waves through the air, Ocean Waves across the surface of the ocean, and Spring which oscillate (move or swing back and forth at a regular speed) such as in a clock.

What affects the speed of a wave?

The medium that the wave moves through. A wave moves at different speeds depending on what it moves through, ex: light, sound, ect. Hence the speed of light and the speed of sound. The properties of the wave don't really affect the speed.

What is a crest?

The point on a wave with the maximum value or upward displacement within a cycle.

What is a longitudinal wave?

Waves that have the same direction of vibration as their direction of travel, which means that the movement of the medium is in the same direction as or the opposite direction to the motion of the wave.

Under what conditions does sound resonance occur?

When a source other than resonating device vibrates at the exact resonant sound of a device

Example of incident ray

When you put a light on a mirror, it gets reflected. This happens because when light is going towards a mirror, this is called an incident ray. When it is reflected, the light coming out is the "reflected ray".

Is it possible for a high amplified musical note to cause a crystal goblet to shatter?

Yes, if the note is at fundamental frequency of the glass, the glass will absorb energy from the sound waves and vibrate in resonance with the note.

Refraction

a change in direction of a wave due to a change in its speed.

Reflection

a change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated.

Frequency?

a musical sound that determines its pitch

polarization

a property of certain types of waves that describes the orientation of their movement back and forth at a regular speed

What does a trough of a sine curve used to represent a sound wave correspond to?

a region of high pressure

The Tacoma Narrows bridge collapsed in 1940 when winds caused _________ to build up in the bridge.

a standing wave

How many harmonics are present when an air column vibrates in a pipe that is open at both ends?

all harmonics are present

What kind of waves does the Doppler effect involve?

all waves

virtual image

an image in which the outgoing rays from a point on the object always diverge

Why can two mechanical waves occupy the same space at the same time?

because the waves are displacements of matter

What is the region of a sound wave in which the density and pressure are greater than normal?

compression

Unlike a transverse wave on a rope, sound travels as a _______________ wave.

compressional

Which of the following can produce a real image: concave mirror, convex mirror, plane mirror?

concave mirror

Pitch depend on the ________ of a sound wave.

frequency

The quality of a musical tone of a certain pitch results from a combination of...

harmonics

A train moves down the track towards an observer. The sound from the train, as heard by the observer, is __________ the sound heard by a passenger on the train.

higher in pitch than

What is a sound wave?

longitudinal waves

The distance between wave fronts of plane waves correspond to __________ of a sound wave.

one wavelength

How many harmonics are present when an air column vibrates in a pipe that is closed at one end?

only odd harmonics are present

What is the highness and lowness of a sound perceived as?

pitch

What happens to pitch when the frequency of a sound wave increases?

pitch rises

At a large distance from a sound source, spherical wave fronts are viewed as...

plane waves

One end of a taut rope is fixed to a post. What type of wave is produced if the free end is quickly raised and lowered one time?

pulse wave

Each trough of a sine wave used to represent a sound wave corresponds to a _________ of a sound wave.

rarefaction

real image

representation of an object source in which the perceived location is actually the point of convergence of the rays of light that make up the image

When the frequency of a force applied to a system matches the natural frequency of a vibration of the system, ________ occurs.

resonance

Audible beats are formed by the interference of two waves of....

slightly different frequencies

In general, sound travels faster through....

solids than through gases

A simple pendulum swings in simple harmonic motion. At maximum displacement...

the acceleration reaches a maximum

The pendulum's amplitude is...

the angle between the string of a pendulum at its equilibrium position and at its maximum displacement

Suppose that two sound waves passing through the same medium have different wavelengths. What would likely be the reason for differing wavelengths?

the differences in frequency

Wavelength

the distance over which the wave's shape repeats

What is a frequency? (in simple harmonic motion)

the number of cycles or vibrations per unit of time

Describe any changes in pitch of the sound a stationary observer hears from the siren of an ambulance passes the observer.

the observer hears a sound with higher pitch than the sound source is emitting. As the source moves, the wave fronts ahead of the source are pushed closer together than they would be if the source were stationary.

Diffraction

the process by which a beam of light or other system of waves is spread out as a result of passing through a narrow aperture or across an edge, typically accompanied by interference between the wave forms produced

Incident pulse/ray

the ray of light that strikes the surface before reflection, transmission, or absorption. The angle of this ray is measured from a normal to the surface.

Compression?

the region of a sound wave in which air molecules are pushed closer together

what features of a given pendulum changes when the pendulum is moved from earth's surface to the moon?

the restoring force

Standing waves are produced by periodic waves of...

the same frequency, amplitude, and wavelength traveling in opposite directions.

Doppler Effect

the shift in frequency and wavelength of waves which results from a source moving with respect to the medium.

When two mechanical waves coincide, the amplitude of the resultant wave is always _________ the amplitudes of each wave alone.

the sum of

Period

the time for a particle on a medium to make one complete vibrational cycle

What is a period? (in simple harmonic motion)

the time required to complete a cycle of motion in a simple harmonic motion

Two waves traveling in opposite directions on a rope meet and undergo complete destructive interference. What best describes the waves a moment after the waves meet and coincide?

the waves continue unchanged

Musical instruments of different types playing the same note may often be identified by the _______ of their sounds.

timbre

NAME THIS WAVE. It travels through a medium. As this wave passes, the particles of the medium vibrate in a direction perpendicular to the direction of the wave's motion.

transverse wave

Fir a standing wave in an air column in a pipe that is open at both ends, there must be at least how many nodes and antinodes?

two antinodes and one node

Consider two identical wave pulses on a rope having a fixed end. Suppose the first pulse reaches the end of the rope, is reflected back, and then meets the second pulse. When the two pulses overlap exactly, what will be the amplitude of the resultant pulse.

zero