Q&A Hero

Q: The speed of light in a particular transparent medium is 1/8 the speed of light in a vacuum. What is the index of refraction of the material?A) 2.7B) 0.38C) 8D) 0.13

Q: A particular material has an index of refraction of 2.25. What percent of the speed of light in vacuum is the speed of light in the material? A) 75% B) 13% C) 25% D) 86%

Q: The speed of light in a material is 2.35 x 108 m/s. What is the index of refraction of this material?A) 1.28B) 0.783C) 2.35D) 0.294

Q: The ratio of the speed of light in a vacuum to the speed of light in a medium is known as the index of A) reflection. B) refraction. C) diffraction. D) none of these.

Q: The bending of light because of a speed change as it moves from one medium to another is called A) diffraction. B) refraction. C) reflection. D) the Doppler effect.

Q: The law of reflection A) applies only to plane mirrors. B) is limited to regular reflection. C) must be modified for diffuse reflection. D) applies to all reflecting surfaces.

Q: A flashlight beam is seen because of A) specular reflection. B) diffuse reflection. C) dispersion. D) refraction.

Q: The bending of waves around corners is called A) reflection. B) refraction. C) diffraction. D) interference.

Q: A pencil partially submerged in a glass of water appears broken or offset because of A) polarization. B) diffraction. C) interference. D) refraction.

Q: When the Sun is on the horizon, it is actually lower than it appears because of A) refraction. B) dispersion. C) scattering. D) reflection.

Q: A ray of light in water strikes an air"water interface at an angle of incidence greater than the critical angle. The ray A) emerges but is bent away from the normal. B) travels along the interface. C) emerges but is bent toward the normal. D) is totally reflected into the water.

Q: A rainbow results from A) both reflection and refraction. B) refraction only. C) neither reflection nor refraction. D) reflection only.

Q: Which of the following statements is true of the angles of incidence and reflection? A) They are not related B) They can never be equal C) They are always equal D) They add to 90.

Q: The angles of incidence and reflection A) are not related. B) can never be equal. C) are measured from a normal to the reflecting surface. D) add to 90.

Q: A reflected ray of light leaves a plane mirror's surface at an angle of 50 relative to the normal. The angle of incidence was A) 50 relative to the surface. B) 50 relative to the normal. C) 90 from the surface. D) none of these.

Q: A reflected ray of light leaves a plane mirror's surface at an angle of 60 relative to the normal. The angle of incidence was A) 60 relative to the surface. B) 30 relative to the normal. C) 90 from the surface. D) none of these.

Q: A light wave traveling in air strikes a plane mirror surface at an angle of 20 relative to the normal. The wave is reflected at an angle of A) 20 relative to the surface. B) 20 relative to the normal. C) 70 relative to the normal. D) none of these.

Q: The angle of incidence of a light wave is A) different depending on whether there is diffuse or specular reflection. B) measured from a normal to the surface. C) equal to the angle of refraction. D) measured relative to the surface of the material.

Q: The law of reflection applies to A) specular reflection. B) diffuse reflection. C) irregular reflection. D) all of these.

Q: If the intensity of a sound is increased by a factor of 100, how is the decibel level affected?

Q: A sound level of 96 dB is how many times as intense as one of 90 dB?

Q: A sound level of 93 dB is how many times as intense as one of 73 dB?

Q: A particular sound with large intensity is reduced 1000-fold. What is the decibel reduction?

Q: The intensity of a 70-dB whistle is doubled. What is the new decibel level?

Q: What is the frequency of yellow-green light that has a wavelength of 550 nm?

Q: A sound wave in air travels at a speed of 340 m/s. If the wavelength is 0.100 m, in what range of the sound spectrum is the wave?

Q: During a thunderstorm, an observer notes that 10 s elapsed between the lightning flash and the sound of the thunder. What is the approximate distance, in miles, from the observer to the lightning?

Q: Approximately how many times faster is the speed of light in vacuum than the speed of sound in air?

Q: How many times greater is the speed of red light (l = 700 nm) than the speed of violet light (l = 400 nm) in a vacuum?

Q: What are the wavelength limits, in meters, of the audible region of the sound spectrum (v= 344 m/s)?

Q: A radar pulse returns 3.0 x 10-4 s after it was sent out and reflected by an object. What is the separation distance of the radar source and the object?

Q: A certain radio wave has a frequency of 1.03 MHz. What is the wavelength?

Q: A certain radio wave has a wavelength of 6.0 x 10-2m. What is its frequency in hertz?

Q: A series of ocean waves, each 6.0 m from crest to crest and moving past an observer at a rate of 2.0 waves per second, has what speed?

Q: What is the frequency, in hertz, of a sound wave (v= 340 m/s) with a wavelength of 0.20 m?

Q: What is the wavelength, in meters, of radio waves produced by a radio station with a frequency of 1400 kHz?(c= 3.00 x 108m/s)

Q: A pendulum has how many natural frequencies?

Q: When a system is being driven at a natural frequency, it is said to be driven in ______________.

Q: For a standing wave in a rope or string, the points that remain stationary are called ______________.

Q: As a truck moves away from a person with its horn blowing, the person hears a frequency ______________ than that of the horn.

Q: An observer moving toward a stationary sound source hears a(n) ______________ in frequency.

Q: If a sound level increases by 30 dB, the intensity increases by a factor of ______________.

Q: When a jet plane exceeds the speed of sound, a(n) ______________ forms, resulting in a sonic boom.

Q: Watts per square meter is a unit for measuring the ______________ of a sound wave.

Q: The loudness of a sound wave is determined by its ______________.

Q: In general, the speed of sound increases as the density of a medium _____________.

Q: Sound is a(n) ______________ wave.

Q: Sounds with frequencies higher than the human ear can detect are in the ______________ range.

Q: A sound with a frequency of 15 Hz is in the ______________ region of the sound spectrum.

Q: Light in a vacuum has a speed of ______________ m/s.

Q: The minimum sound intensity that can be detected by the human ear is called the ______________ of hearing.

Q: The audible range of sound is from 20 Hz to ______________ kHz.

Q: For a wave with a constant speed, the smaller the period, the ______________ its wavelength.

Q: For a wave with a constant speed, the greater the frequency of the wave, the _____________ its wavelength.

Q: Of the two main types of waves, light is a(n) ______________ wave.

Q: A wave in which the particle displacement is parallel to the wave motion is called a(n) ______________ wave.

Q: A wave in which the particle displacement is perpendicular to the wave motion is called a(n) ______________ wave.

Q: The frequency and the wavelength of a wave are ______________ proportional.

Q: If the wave frequency is doubled, the period of the wave is ______________.

Q: The relationship of wave speed, wavelength, and frequency is given by ______________.

Q: The SI unit of frequency is ______________.

Q: A wave with a frequency of 5 Hz will have a period of ______________ s.

Q: All waves transfer ______________.

Q: A wave is a propagation of ______________.

Q: What is the wavelength in meters, of a sound wave (v= 340 m/s) with a frequency of 4 Hz? A) 85 Hz B) 1360 Hz C) 340 Hz D) 0.012 Hz

Q: What is the frequency, in hertz, of a sound wave (v= 340 m/s) with a wavelength of 10 m? A) 34 Hz B) 3400 Hz C) 340 Hz D) 0.029 Hz

Q: A stretched string can have ______________ natural frequency(ies). A) one B) 10 times its length in C) 5 times its length in D) many

Q: When an oscillator is driven in resonance, A) there are no standing waves. B) any driving frequency may be used. C) all natural frequencies are present. D) there is maximum energy transfer.

Q: Resonance occurs when A) two different objects vibrate with different frequencies. B) two different objects produce beats. C) an object having a certain natural frequency is set in vibration by a second object vibrating at that frequency. D) an object produces a sound.

Q: Standing waves can be set up in a string when two waves that are A) of the same frequency and amplitude, but are opposite in direction of travel, meet each other. B) of the same frequency, amplitude, and direction of travel are also 180 out of phase. C) of the same frequency, amplitude, and direction of travel meet each other. D) of the same frequency, amplitude, and velocity meet each other.

Q: For the Doppler effect to occur, there must be A) a moving source. B) a moving observer. C) relative motion between a source and an observer. D) no motion.

Q: A train sounding its horn is moving toward an observer. The pitch of the horn's sound relative to its normal pitch is A) lower. B) sometimes higher and sometimes lower. C) higher. D) the same.

Q: During a thunderstorm, an observer notes that 20 s elapsed between the lightning flash and the sound of the thunder. What is the approximate distance, in miles, from the observer to the lightning? A) 20 mi B) 100 mi C) 4 mi D) 400 mi

Q: The Doppler effect is observed only when A) the source of a wave moves toward a stationary observer. B) there is relative motion between the source of a wave and an observer. C) an observer moves toward the stationary source of a wave. D) both the source of a wave and an observer are moving toward each other.

Q: Light can travel to Earth from a distant star, but sound cannot. Why is this? A) Light is an electromagnetic wave, and sound requires a medium. B) The Sun does not make sound. C) Light is a longitudinal wave, and sound is a transverse wave. D) The statement is false; both light and sound can travel in empty space.

Q: How many times greater is the speed of red light (l = 700 nm) than the speed of ultraviolet light (l = 380 nm) in a vacuum?A) 1.84 , the first color of light is fasterB) 0.54 , the second color of light is fasterC) 3.00 x 108, the first color of light is fasterD) 1.00 , both colors of light have the same speedE) 3.00 x 108, the second color of light is faster

Q: How many times greater is the speed of infrared light (l = 800 nm) than the speed of violet light (l = 400 nm) in a vacuum? A) 2 B) 1/2 C) 400 D) 1; that is, both have the same speed.

Q: A Doppler red shift indicates A) a shift toward lower frequencies. B) a shift toward shorter wavelengths. C) that a light source is approaching relative to the observer. D) none of these.

Q: A Doppler red shift indicates A) a shift toward higher frequencies. B) a shift toward longer wavelengths. C) that a light source is approaching relative to the observer. D) none of these.

Q: A Doppler red shift indicates A) a shift toward higher frequencies. B) a shift toward shorter wavelengths. C) that a light source is receding relative to the observer. D) none of these.