Exam 15: Wave Motion

An equation that gives the particle displacement for a medium in which there is a simple harmonic traveling wave is Y(x, t) = (2/ $\pi$ ) sin $\pi$ (3x + 2t), Where x and y are in centimeters and t is in seconds. At t = 2 s the speed of a particle at the location x = 4 cm is

The intensity of a certain spherical wave is 8.0 W/m² at a distance of 1.0 m from the source. If the medium is isotropic and nonabsorbing, the intensity 100 m from the source is

Electromagnetic waves

Waves of amplitude 1.3 cm move along a 14-m long string that has a mass of 90 g and is under a tension of 18 N. If the average total energy of the waves in the string is 5 J, calculate the frequency of the waves.

If you were to quadruple the speed of a wave on a string while keeping the frequency and amplitude of the wave constant, the rate at which energy is delivered by the wave would

The pulse shown is moving in the string toward a fixed end at the wall. After reflection at the wall, which figure correctly represents the pulse?

A blue line in the spectrum of the hydrogen atom has a wavelength $\lambda$ = 486 nm. In the hydrogen-atom spectrum emitted by a distant galaxy, this line is observed on Earth at $\lambda$ = 550 nm. With what speed is this galaxy receding from us? (The speed of light is 3.0 $\times$ 10⁸ m/s.)

A wave moving in the positive x direction has an amplitude of 0.4 m, a frequency of 0.25 Hz, and a wavelength of 24 m. An equation, in which the units are SI, that might describe this wave is

The graph shows a wave of frequency 3.0 Hz traveling to the right. The phase velocity of this wave is

A whistle is whirled around in a horizontal circle 120 times a minute at the end of a piece of string 1.5 m in length. If the standard frequency of the whistle is 550 Hz, calculate the difference between the highest and lowest frequencies heard by a stationary observer (assume the speed of sound in air = 343 m/s).

In a sinusoidal traveling wave, the distance between two points that differ in phase by 2 $\pi$ radians is the

The sound intensity in front of a loudspeaker diaphragm vibrating at 2 kHz is 4.3 W/m², with an acoustic power output of 0.3 W. Calculate the diameter of the diaphragm.

A string exactly two meters long has a mass of 10.0 g and is under a tension of 12.5 N. The speed of a transverse wave in this string is

Suppose the apparent wavelength of the known lines in the spectrum of hydrogen are measured to increase by 50% when light from a distant galaxy is observed on Earth (this is known as the Red Shift). Calculate the speed of recession of the galaxy relative to Earth as a percentage of the speed of light.

A wave given with amplitude A = 10 cm travels along a cord which has two sections, one with linear density 0.1 kg/m and the other with linear density 0.2 kg/m. The wave travels along the cord from the lighter density to the heavier. If the tension in the cord is 50 N, the amplitude of the reflected wave is

A stationary ship generates a sound signal at the bow and has a receiver system at the stern of the ship 100 m away. The signal arriving at the stern traveling directly through the air and the signal reflected from the sea bottom arrive at the sensor at the same time. If the velocity of sound in air is 331 m/s and in water is 1435 m/s, calculate the depth of water below the ship.

The graph shows a wave traveling to the right with a velocity of 4 m/s. The equation that best represents the wave is

A string under tension carries a transverse wave traveling at speed v. If the tension in the string is quadrupled and the linear density of the string is doubled, what is the wave speed?

A string of mass 2.4 $\times$ 10^-3 kg and length 0.60 m vibrates transversely in such a way that its fundamental frequency is 100 Hz. The tension on this string must be approximately

If you were to double the frequency of a wave on a string while keeping the speed and amplitude of the wave constant, the energy delivered by the wave would