Q&A Hero

Q: The source of a sonic boom A) must be a sound emitter. B) may or may not be a sound emitter. C) is not a sound emitter. D) none of the above

Q: As a supersonic aircraft increases in speed, the angle of its V-shaped shock wave becomes A) wider. B) narrower. C) both of these D) neither of these

Q: A sonic boom is produced by an airplane flying at a speed A) just below the speed of sound. B) equal to the speed of sound. C) greater than the speed of sound. D) all of the above E) none of the above

Q: A shock wave is A) the opposite of a bow wave. B) usually composed of a pair of closely spaced cones. C) weak for aircraft that fly at less than the speed of sound. D) all of the above E) none of the above

Q: An aircraft that flies faster than the speed of sound is said to be A) subsonic. B) supersonic. C) impossible. D) none of the above

Q: A shock wave is produced when a wave source moves A) nearly as fast as the waves it produces. B) as fast as the waves it produces. C) faster than the waves it produces. D) none of the above

Q: A bow wave is produced when a speed boat moves A) nearly as fast as the waves it produces. B) as fast as the waves it produces. C) faster than the waves it produces. D) none of the above

Q: If you quickly run away from the orchestra at a concert, the frequency of the sound you hear will be A) decreased. B) increased. C) neither of these.

Q: If you quickly run toward the orchestra at a concert, the frequency of the sound you hear will be A) decreased. B) increased. C) neither of these

Q: A blue shift for light indicates that the light source is moving A) toward you. B) away from you. C) both of these D) neither of these

Q: A red shift for light indicates that the light source is moving A) toward you. B) away from you. C) both of these D) neither of these

Q: A Doppler effect occurs when a source of sound moves A) towards you. B) away from you. C) either of these D) neither of these

Q: In the Doppler effect it is important to distinguish between A) frequency and speed. B) speed and velocity. C) speed and acceleration. D) distance and displacement.

Q: The Doppler effect is characteristic of A) water waves. B) sound waves. C) light waves. D) all of the above E) none of the above

Q: The number of nodes, including the end points, in a standing wave that is three wavelengths long is A) 4. B) 5. C) 6. D) 7. E) none of the above

Q: The number of nodes, including the end points, in a standing wave that is two wavelengths long is A) 1. B) 2. C) 3. D) 4. E) none of the above

Q: A node is a position of A) minimum amplitude. B) maximum amplitude. C) half amplitude.

Q: A standing wave is likely produced when A) two waves overlap. B) a wave reflects upon itself. C) the speed of the wave is zero or near zero. D) the amplitude of a wave exceeds its wavelength.

Q: Wave interference occurs for A) sound waves. B) light waves. C) water waves. D) all of the above E) none of the above

Q: To say that one wave is out of phase with another is to say that the waves are A) of different amplitudes. B) of different frequencies. C) of different wavelengths. D) out of step. E) all of the above

Q: Interference is a property of A) sound waves. B) water waves. C) light waves. D) all of the above E) none of the above

Q: A skipper on a boat sees wave crests passing the anchor chain every 5 seconds and estimates the distance between crests is 15 m. What is the speed of the water waves? A) 3 m/s B) 5 m/s C) 15 m/s D) need more information

Q: Water waves pass by a piece of cork floating on the water that bobs up and down one complete cycle each second. The waves are 2 meters long. What is the speed of the wave? A) 0.25 m/s B) 0.50 m/s C) 1.0 m/s D) 2 m/s E) 4 m/s

Q: A wave oscillates up and down two complete cycles each second. If the wave travels an average distance of 6 meters in one second, its wavelength is A) 0.5 m. B) 1 m. C) 2 m. D) 3 m. E) 6 m.

Q: The distance traveled by a wave during a single period is A) one-half wavelength. B) one wavelength. C) two wavelengths. D) none of the above

Q: A wave travels an average distance of one meter in one second with a frequency of 1 hertz. Its amplitude is A) less than 1 meter. B) 1 meter. C) more than 1 meter. D) need more information

Q: A floating leaf oscillates up and down two complete cycles in one second as a 10-meter long water wave passes by. What is the wave's speed? A) 2 m/s B) 10 m/s C) 20 m/s D) 40 m/s E) more than 40 m/s

Q: A water wave passes by a floating leaf that is made to oscillate up and down two complete cycles each second, which means that the wave's frequency is A) 0.5 Hz. B) 1 Hz. C) 2 Hz. D) 3 Hz. E) 6 Hz.

Q: What is the wave speed of a wave traveling an average distance of 6 meters in one second? 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

Q: Which equation is correct for wave speed? A) wave speed = frequency x wavelength B) wave speed = (1/period) x wavelength C) both of these D) neither of these

Q: Which of these is a transverse wave? A) a Slinky shaken to and fro. B) a radio wave C) a sound wave D) all of the above E) none of the above

Q: The vibrations of a longitudinal wave move A) along the direction of wave travel. B) at right angles to the direction of wave travel. C) that changes with speed.

Q: The vibrations of a transverse wave move A) along the direction of wave travel. B) at right angles to the direction of wave travel. C) that changes with speed.

Q: Which of these is a longitudinal wave? A) sound B) light C) radio D) all of the above E) none of the above

Q: The compressions and rarefactions in a longitudinal wave travel in A) the same direction. B) opposite directions. C) a vacuum.

Q: All waves have in common a A) pattern. B) vibrating source. C) variable regions of high and low pressure. D) none of the above

Q: Radio waves travel at the speed of light, 300,000 km/s. The wavelength of a radio wave received at 100 megahertz is A) 0.3 m. B) 3.0 m. C) 30 m. D) 300 m. E) none of the above

Q: A 101-MHz radio wave has vibrations per second of A) less than 101,000,000. B) 101,000,000. C) more than 101,000,000.

Q: Repeatedly dipping your fingers into water produces waves. Increasing the frequency of dipping produces waves that are A) shorter. B) longer. C) the same.

Q: Some of a wave's energy dissipates as heat. In time, this will reduce the wave's A) speed. B) wavelength. C) amplitude. D) frequency. E) period.

Q: The period of the second hand on a clock is A) 1 second. B) 1/60 second. C) 60 seconds. D) 3600 seconds. E) 12 hours.

Q: The frequency of the second hand on a clock is A) 1 hertz. B) 1/60 hertz. C) 60 hertz.

Q: A weight suspended from a spring bobs up and down over a distance of 1 meter in two seconds. Its frequency is A) 0.5 hertz. B) 1 hertz. C) 2 hertz. D) none of the above

Q: An object that completes 100 vibrations in 5 seconds has a period of A) 0.5 second. B) 1 second. C) 2 seconds. D) none of the above

Q: An object that completes 20 vibrations in 10 seconds has a frequency of A) 0.5 hertz. B) 1 hertz. C) 2 hertz. D) 200 hertz.

Q: An object that completes 10 vibrations in 20 seconds has a frequency of A) 0.5 hertz. B) 2 hertz. C) 200 hertz.

Q: If you double the frequency of a vibrating object, its period A) doubles. B) halves. C) is quartered.

Q: A 60-vibration-per-second wave travels 30 meters in 1 second. Its frequency is A) 30 hertz and it travels at 60 m/s. B) 60 hertz and it travels at 30 m/s. C) 1800 hertz and it travels at 2 m/s. D) none of the above

Q: The frequency of a certain wave is 10 hertz and its period is A) 0.1 second. B) 10 seconds. C) 100 seconds. D) none of the above

Q: The frequency of a simple pendulum does NOT depend on A) its mass. B) its length. C) the acceleration due to gravity. D) all of the above E) none of the above

Q: A fishing-boat captain returns to port saying, "It's rough out there with waves that are 4 meters high." He is probably talking of waves of amplitude A) 1 m. B) 2 m. C) 3 m. D) 4 m.

Q: The amplitude of a wave is 1 meter. The crest-to-trough distance of the wave is A) 0.5 m. B) 1 m. C) 2 m. D) none of the above

Q: Both a transverse wave and a longitudinal wave have A) amplitude. B) frequency. C) wavelength. D) speed. E) all of the above

Q: The source of all waves is A) something that vibrates. B) energy. C) a force of some kind. D) all of the above E) none of the above

Q: When an elevator is accelerating upward, the frequency of a pendulum inside A) increases. B) decreases. C) doesn't change.

Q: The stride of a horse would be quicker if more mass in its legs were concentrated A) in the upper part, nearer the horse's body. B) towards its feet. C) halfway up its legs. D) uniformly all along its legs. E) none of the above

Q: A pendulum clock at high altitudes runs A) fast. B) slow. C) normally as it does at sea level.

Q: If a child swinging to and fro on a playground swing stands up, her time for a to-and-fro swing is A) longer. B) shorter. C) unchanged.

Q: The pendulum with the greatest frequency is one with the A) shortest length. B) longest length. C) neither of these

Q: Which of these is affected by mass? A) a freely-falling object B) an object sliding down a friction-free plane C) a pendulum D) all of the above E) none of the above

Q: A wiggle in both space and time is a A) vibration. B) wave. C) both of these D) neither of these

Q: A wiggle in time is a A) vibration. B) wave. C) both of these D) neither of these

Q: Processes can proceed from disorder to order A) when input energy is supplied. B) on an everyday occurrence. C) never. D) none of the above

Q: The most disorderly arrangement of energy within matter is also A) the least probable state of matter. B) the most probable state of matter. C) a matter of certainties, not probabilities. D) none of the above

Q: A quantity of water has more entropy when it is A) frozen ice. B) boiling. C) at room temperature.

Q: As a system becomes more disordered, entropy A) increases. B) decreases. C) remains the same.

Q: Entropy is most closely related to the A) first law of thermodynamics. B) second law of thermodynamics. C) both of these D) neither of these

Q: Entropy measures temperature A) at constant pressure. B) at constant volume. C) as pressure increases. D) all of the above E) none of the above

Q: Systems alone tend to move toward a state of A) less entropy. B) more entropy. C) no entropy. D) none of the above

Q: Systems alone tend to move toward A) order. B) disorder. C) temperature inversions. D) none of the above

Q: Entropy is a measure of A) messiness. B) disorder. C) both of the above D) none of the above

Q: High-quality energy in natural processes has a tendency to transform into A) higher quality energy. B) lower quality energy. C) internal energy. D) entropy. E) none of the above

Q: The ideal efficiency for a heat engine operating between the temperatures of 227C and 27C is A) 20%. B) 25%. C) 40%. D) 88%. E) none of the above

Q: The ideal efficiency for a heat engine operating between the temperatures 2700 K and 300 K is A) 10%. B) 24%. C) 80%. D) 89%. E) none of the above

Q: Harry places a new air conditioner in the middle of his hot room, which when operating A) cools the room. B) further warms the room. C) neither of these

Q: If you leave the refrigerator door open in a closed room, the room temperature will A) increase. B) decrease. C) be unaffected.

Q: Two identical blocks of iron are placed in contact, one at 10oC and the other at 20oC. If the cooler block cools to 5oC and the warmer block warms to 25oC, this would violate the A) first law of thermodynamics. B) second law of thermodynamics. C) third law of thermodynamics. D) none of the above

Q: More efficient gasoline engines could be built if they could withstand A) greater rotational rates. B) lower temperatures. C) higher temperatures. D) none of the above

Q: A heat engine would have 100% efficiency if its low-temperature reservoir were A) as hot as its reservoir. B) at absolute zero. C) either of these D) neither of these

Q: The greater the temperature difference between input and output reservoirs of a heat engine, the A) greater the efficiency. B) smaller the efficiency. C) both of the above D) none of the above