Q&A Hero

Q: According to quantum physics, measuring the temperature of lava from a distant volcano by photographing its color with a telescopic camera measurably affects the lava's temperature. A) True B) False C) both of these depending on circumstances

Q: The uncertainty principle tells us that the more information one has about the energy of an electron, the less certain one is about A) its position. B) the time it has that energy. C) both of these D) neither of these

Q: The more we know about a particle's position, the less we know about its A) speed. B) momentum. C) kinetic energy. D) all of the above E) none of the above

Q: A radiation detector measures radioactivity decay of a piece of radium by catching and counting alpha particles it emits. Making this measurement affects the A) radiation rate of the piece of radium. B) alpha particles that are caught and counted. C) both of these D) neither of these

Q: At the beach you see a friend facing away from you. Keeping quiet you can cause her to turn around by A) staring intently at her back. B) tossing small pebbles at her back. C) although staring will be less effective, both will affect a turn-around. D) none of the above

Q: Casually sneaking a quick peek at a photo in your mobile phone A) adds energy to the photo. B) subtracts energy from the photo. C) brings you into an observer-observed relationship that intrigues some science types. D) changes the phone itself E) none of the above

Q: By adjusting a TV image with a remote you can A) affect only the image. B) participate with the action on the screen. C) both of these D) neither of these

Q: By casually glancing at a scene on your TV you are A) affecting the image. B) participating in the action on the screen. C) both of these D) neither of these

Q: When you adjust a telescope to get a clear image of Saturn's rings, in a small but measurable way you alter A) the telescope. B) Saturn's rings. C) both of these D) neither these

Q: When you adjust a telescope to get a clear image of Saturn's rings, there is a perceptible interaction between A) you and the telescope. B) you and Saturn's rings. C) both of these D) neither these

Q: In placing a cool thermometer into a hot cup of tea you likely are A) affecting its temperature. B) draining energy from the tea. C) both of these D) neither of these

Q: In casually observing a cup of tea you are A) affecting its temperature. B) affecting its location. C) both of these D) neither of these

Q: According to your textbook, popular confusion is lessened when applying Heisenberg's uncertainty principle by heeding the distinction between A) momentum and energy. B) energy and time. C) passive observation and probing.

Q: The Heisenberg uncertainty principle states that A) Planck's constant sets a limit on accuracy of measurements. B) we can't simultaneously measure exactly both the position and momentum of a particle. C) we can't simultaneously measure exactly a particle's energy and time having that energy. D) all of the above

Q: The formula △p △ x≥ h tells us that the product of △p and △x cannot be A) less than h B) greater than h C) equal to h

Q: In Heisenberg's formula, △p △x≥ h, the h symbolizes A) Planck's constant. B) an average value of Planck's constant. C) the peak value of Planck's constant. D) Planck's constant divided by 2π. E) none of the above

Q: In Heisenberg's formula, △p △x≥ h, the △ symbolizes A) increase in. B) decrease in. C) change in. D) uncertainty of. E) certainty of.

Q: According to Heisenberg's uncertainty principle, the more we know about a particle's momentum, the less we know about its A) kinetic energy. B) mass. C) speed. D) location. E) none of the above

Q: Heisenberg's uncertainty principle applies to A) momentum and position. B) energy and time. C) both of these D) neither of these

Q: Quantum uncertainties are most predominant for simultaneously measuring the speed and location of A) a baseball. B) a spitball. C) an electron. D) none of the above

Q: Heisenberg's uncertainty principle is A) noticeable only for submicroscopic particles. B) a fundamental principle in quantum mechanics. C) predominant in the atomic domain. D) all of the above E) none of the above

Q: What is conserved when a photon collides with an electron? A) momentum B) energy C) both of these D) neither of these

Q: Which of the following has the longer wavelength? A) a low-energy electron B) a high-energy electron C) both the same D) none of the above

Q: An electron and a baseball move at the same speed. Which has the longer wavelength? A) the electron B) the baseball C) both the same D) none of the above

Q: An electron and a proton are traveling at the same speed. Which has the longer wavelength? A) the electron B) the proton C) both the same D) none of the above

Q: A bullet and a proton have the same momentum. Which has the longer wavelength? A) the bullet B) the proton C) both the same

Q: If a proton and an electron have the same momentum, the longer wavelength belongs to the A) proton. B) electron. C) both the same

Q: Two photons that have the same wavelength also have the same A) frequency. B) energy. C) both of these D) neither of these

Q: Which can undergo diffraction? A) photons. B) electrons. C) positrons. D) all of the above E) none of the above

Q: An electron microscope makes use of A) short wavelengths of light. B) the wave nature of electrons. C) electron attraction and repulsion. D) electron current. E) the inertia of electrons.

Q: The wavelength of a particle relates to its A) momentum. B) energy levels. C) quantum number. D) all of the above E) none of the above

Q: According to Louis de Broglie, a material particle has A) particle properties. B) wave properties. C) both of these D) neither of these

Q: Which produces an interference pattern when directed through two suitably spaced slits? A) light B) sound C) electrons D) all of the above E) none of the above

Q: Very low-intensity light passing through a double slit produces a pattern that A) is built up one photon at a time. B) reveals which slit each photon passed through. C) changes only in intensity as time passes, not in detailed structure.

Q: After passing through double slits, electrons make a pattern on a screen that A) shows which slit each electron has passed through. B) resembles a pattern that waves make. C) has two peaks of intensity. D) has a single wide peak of intensity.

Q: The wave-particle duality applies to A) photons. B) electrons. C) protons D) all of the above E) none of the above

Q: Light behaves primarily as a particle when it A) travels from one place to another. B) interacts with matter. C) both of these D) neither of these

Q: Light behaves primarily as a wave when it A) travels from one place to another. B) interacts with matter. C) both of these D) neither of these

Q: Taking the work function into account, electrons ejected from a photosensitive material have A) less kinetic energy than the absorbed photon's energy. B) more kinetic energy than the absorbed photon's energy. C) kinetic energy equal to the absorbed photon's energy.

Q: In photoelectric emission, the work function is the minimum A) frequency of light to produce emission. B) energy required to eject an electron from the surface. C) energy an emitted electron possesses. D) none of the above

Q: To study the energy of photoelectrons we measure A) the potential difference required to stop them. B) the distance traveled in a given time. C) the time taken to travel a given distance. D) their temperature.

Q: The physics underlying photovoltaic solar cells is A) electron diffraction. B) photon capture. C) the photoelectric effect. D) none of the above

Q: When ejected electrons from a photosensitive surface are confined within the material we have a A) photovoltaic cell. B) light-emitting diode. C) both of these D) none of these

Q: If we increase the brightness of violet light shining on a photosensitive surface we also increases the A) number of electrons ejected per second. B) kinetic energy of the ejected electrons. C) threshold frequency. D) time lag between the absorption of blue light and ejection of electrons. E) none of the above

Q: A photosensitive surface is illuminated with both blue and violet light. The light that causes the greater number of ejected electrons is A) blue light. B) violet light. C) both eject equal numbers. D) need more information

Q: The greater the frequency of the illuminating light on a photosensitive surface, the greater the A) number of ejected electrons. B) velocity of ejected electrons. C) both of these D) neither of these

Q: In the photoelectric effect, the brighter the illuminating light on a photosensitive surface, the greater the A) number of ejected electrons. B) velocity of ejected electrons. C) both of these D) neither of these

Q: Which experiment best illustrates the particle-like nature of light? A) photoelectric effect B) double-slit experiment C) both of these D) neither of these

Q: The photoelectric effect supports a A) wave nature of light. B) particle nature of light. C) both of these D) none of these

Q: The phenomenon easily explained only in terms of the particle model of light is A) reflection. B) refraction. C) photoelectric effect. D) diffraction. E) none of the above

Q: Hypothetically, if Planck's constant were smaller, atoms would be A) larger. B) smaller. C) no different in physical size.

Q: Two pulses of light, one red and one blue, have the same energy. The pulse with the greater number of photons is the A) red pulse. B) blue pulse. C) both the same

Q: Which of the following is quantized? A) energy B) radiation C) number of atoms in a gold bar D) electric charge E) all of the above

Q: The photons having least energy are those of A) infrared. B) red light. C) green light. D) blue light. E) ultraviolet.

Q: The photons having greatest energy are those of A) infrared. B) red light. C) green light. D) blue light. E) ultraviolet.

Q: Which has more energy per photon? A) red light B) blue light C) both the same

Q: Applying E = hf to photon emission from an atom, the symbol E represents the energy A) of the emitted photon. B) difference between atomic energy levels producing the photon. C) both of these D) neither of these

Q: In the equation E = hf, the symbol h stands for A) half-life. B) momentum as it pertains to light. C) energy per photon wavelength. D) none of the above

Q: In the equation E = hf, the symbol E stands for A) excitation. B) efficiency. C) energy. D) all of the above

Q: In the equation E = hf, the symbol f stands for A) wave frequency. B) wavelength. C) rate at which photons are emitted. D) none of the above

Q: The ratio of a photon's energy to its frequency is A) its speed. B) its wavelength. C) its amplitude. D) Planck's constant. E) none of the above

Q: The ratio of the energy of a photon to its frequency is A) π. B) Planck's constant. C) photon speed. D) photon wavelength. E) unknown.

Q: The first to be credited with the idea that light is quantized was A) Max Planck. B) Albert Einstein. C) both Planck and Einstein at about the same time.

Q: The first to be credited with the idea that energy was quantized was A) Max Planck. B) Albert Einstein. C) both Planck and Einstein at about the same time.

Q: A quantum of light is called A) a proton. B) a neutron. C) an electron. D) a neutrino. E) none of the above

Q: A lump of energy associated with light is called a A) quantum. B) photon. C) both of these D) neither of these

Q: Light from a lit match originates with accelerating A) electrons. B) protons. C) neutrons. D) all of the above

Q: A laser cannot emit more energy than is put into it. But in instances where stored energy can be released in a very short time, the laser A) puts out more energy than is put into it. B) has a greater power output than power input. C) both of these D) neither of these

Q: The red laser beam from a helium-neon laser corresponds to a spectral line of A) helium. B) neon. C) both of these D) neither of these

Q: A helium-neon laser beam in a vacuum is A) red. B) orange. C) white. D) invisible. E) none of the above

Q: The efficiency of classroom-demonstration lasers is typically A) about one percent. B) about ten percent. C) about twenty percent. D) more than twenty percent.

Q: Light from a laser is A) monochromatic. B) in phase. C) coherent. D) all of the above E) none of the above

Q: Compared to the energy put into a laser, the energy of the laser beam is A) usually much more. B) much less. C) the same. D) none of the above

Q: White-light LEDs employ A) phosphors. B) white-emitting diodes. C) extra-high electrical barriers. D) none of the above

Q: Which light source is more energy-efficient? A) a fluorescent lamp B) an incandescent lamp C) a CFL D) an LED

Q: Which of these lamps employs semi-conductor technology? A) incandescent lamp B) fluorescent lamp C) CFL D) LED

Q: The lamp most similar to the common fluorescent lamp is the A) LED. B) CFL. C) incandescent lamp. D) none of the above

Q: Which of these lamps has no mercury content? A) fluorescent lamp B) CFL C) incandescent lamp D) none of the above

Q: To keep chickens in a chicken coop warm, the kind of lamp to use is A) fluorescent. B) CFL. C) incandescent. D) LED. E) all about the same

Q: Argon rather than air is the gas used in incandescent bulbs because A) it produces a pleasing bluish glow. B) oxygen in air oxidizes the lamp filament. C) argon is relatively plentiful. D) none of the above