Which theory of light, the wave theory or the particle

Which theory of light, the wave theory or the particle theory, did the findings of Young, Maxwell, and Hertz support?

What exactly did Max Planck consider quantized: the energy of vibrating atoms or the energy of light itself?

In the formula E 5 hf, does f stand for wave frequency, as defined in Chapter 19?

Which has the lower energy quanta: red light or blue light? Radio waves or X-rays?

Which are more successful in dislodging electrons from a metal surface: photons of violet light or photons of red light? Why?

Why won’t a very bright beam of red light impart more energy to an ejected electron than a feeble beam of violet light?

Why do photographs in a book or magazine look grainy when magnified?

Does light behave primarily as a wave or as a particle when it interacts with the crystals of matter in photographic film

Does light travel from one place to another in a wavelike or a particle-like way?

Does light interact with a detector in a wavelike or a particle-like way?

When does light behave as a wave? When does it behave as a particle?

What evidence can you cite for the wave nature of particles?

In which of the following are quantum uncertainties significant: measuring simultaneously the speed and location of a baseball; of a spitball; of an electron?

When electrons are diffracted through a double slit, do they hit the screen in a wavelike way or in a particle-like way? Is the pattern of hits wavelike or particle-like?

If measurements show a precise position for an electron, can those measurements show the precise momentum also?

What is the uncertainty principle with respect to momentum and position?

If a measurement shows a precise value for the energy radiated by an electron, can that measurement show a precise time for this event as well?

What is the distinction in this book between passively and actively observing an event?

What is the principle of complementarity?

Cite evidence that the idea of opposites as components of a wholeness preceded Bohr’s principle of complementarity.

A typical wavelength of infrared radiation emitted by your body is 25 mm (\(2.5 \times 10^{-2}\) m). Show that the energy per photon of such radiation is about \(8.0 \times 10^{-24}\) J Text Transcription: 2.5 times 10^-2 8.0 times 10^-24

Consider the de Broglie wavelength of an electron that strikes the back face of one of the early models of a TV screen at 1/10 the speed of light. Show that the electron wavelength is \(2.4 \times 10^{-11}~\mathrm m\).

You decide to roll a 0.1-kg ball across the floor so slowly that it will have a small momentum and a large de Broglie wavelength. If you roll it at 0.001 m/s, what is its wavelength? How does this compare with the de Broglie wavelength of the high-speed electron in the preceding problem?

What does it mean to say that something is quantized?

Distinguish between classical physics and quantum physics.

In Chapter 30, we learned the formula \(E \sim f\). In this chapter, we learned the formula E = hf. Explain the difference between these two formulas. What is h? Text Transcription: E sim f

The frequency of violet light is about twice that of red light. How does the energy of a violet photon compare with the energy of a red photon?

Which has more energy: a photon of visible light or a photon of ultraviolet light?

We speak of photons of red light and photons of green light. Can we speak of photons of white light? Why or why not?

Which laser beam carries more energy per photon: a red beam or a green beam?

If a beam of red light and a beam of blue light have exactly the same energy, which beam contains the greater number of photons?

In the photoelectric effect, does brightness or frequency determine the kinetic energy of the ejected electrons? Which determines the number of the ejected electrons?

A very bright source of red light has much more energy than a dim source of blue light, but the red light has no effect in ejecting electrons from a certain photosensitive surface. Why is this so?

Why are ultraviolet photons more effective at inducing the photoelectric effect than photons of visible light?

Why does light striking a metal surface eject only electrons, not protons?

Does the photoelectric effect mainly depend on the wave nature or the particle nature of light?

Explain how the photoelectric effect is used to open automatic doors when someone approaches.

Explain briefly how the photoelectric effect is used in the operation of at least two of the following: an electric eye, a photographer’s light meter, the soundtrack of a predigital motion picture.

If you shine an ultraviolet light on the metal ball of a negatively charged electroscope (shown in Questions 56 and 57 in Chapter 22), it will discharge. But if the electroscope is positively charged, it won’t discharge. Can you venture an explanation?

Does Einstein’s explanation of the photoelectric effect invalidate Young’s explanation of the double-slit experiment? Explain

The camera that took the photograph of the woman’s face (see Figure 31.5) used ordinary lenses that are well known to refract waves. Yet the step-by-step formation of the image is evidence of photons. How can this be? What is your explanation?

What evidence can you cite for the wave nature of light? For the particle nature of light?

When does a photon behave like a wave? When does it behave like a particle?

Light has been argued to be a wave and then a particle, and then back again. Does this indicate that light’s true nature probably lies somewhere between these two models?

How might an atom obtain enough energy to become ionized?

What laboratory device utilizes the wave nature of electrons?

An X-ray photon can hit an electron without that electron picking up all the photon’s energy. Make a hypothesis about the frequency of the photon that “leaves the scene” of the collision. (This phenomenon is called the Compton effect.)

A hydrogen atom and a uranium atom move at the same speed. Which possesses more momentum? Which has the longer wavelength?

If a cannonball and a BB have the same speed, which has the longer wavelength?

What principal advantage does an electron microscope have over an optical microscope?

Would a beam of protons in a “proton microscope” exhibit greater or less diffraction than electrons of the same speed in an electron microscope? Defend your answer.

Suppose nature were entirely different so that an infinite number of photons would be needed to make up even the tiniest amount of radiant energy, the wavelength of material particles was zero, light had no particle properties, and matter had no wave properties. This would be the classical world described by the mechanics of Newton and the electricity and magnetism of Maxwell. What would be the value of Planck’s constant for such a world with no quantum effects?

Consider one of the many electrons on the tip of your nose. If somebody looks at it, will its motion be altered? How about if it is viewed with one eye closed? With two eyes open, but crossed? Does Heisenberg’s uncertainty principle apply here?

Does the uncertainty principle tell us that we can never know anything for certain?

Do we inadvertently alter the realities that we attempt to measure in a public opinion survey? Does Heisenberg’s uncertainty principle apply here?

When checking the pressure in tires, some air escapes. Why doesn’t Heisenberg’s uncertainty principle apply here?

If the behavior of a system is measured exactly for some period of time and is understood, does it follow that the future behavior of that system can be exactly predicted? (Is there a distinction between properties that are measurable and properties that are predictable?

If a butterfly causes a tornado, does it make sense to eradicate butterflies? Defend your answer.

We hear the expression “taking a quantum leap” to describe large changes. Is the expression appropriate? Defend your answer.

To measure the exact age of Old Methuselah, the oldest living tree in the world, a Nevada professor of dendrology, aided by an employee of the U.S. Bureau of Land Management, cut the tree down in 1965 and counted its rings. Is this an extreme example of altering that which you measure or an example of academic misbehavior?

Silver bromide (AgBr) is a light-sensitive substance used in some types of photographic film. To cause exposure of the film, it must be illuminated with light having sufficient energy to break apart the molecules. Discuss the reason this film could be handled without exposure in a darkroom illuminated with red light. How about blue light? How about very bright red light relative to very dim blue light?

Phosphors on the inside of fluorescent lamps convert ultraviolet light to visible light. Discuss the absence of substances that convert visible light to ultraviolet light

Sunburn produces cell damage in the skin. Why is ultraviolet radiation capable of producing this damage, while visible radiation, even if more intense, is not?

One of the technical challenges facing the original developers of color television was the design of an image tube (camera) for the red portion of the image. From an energy point of view, discuss why finding a material that would respond to red light was more difficult than finding materials to respond to green and blue light.

Discuss how the reading of the meter in Figure 31.1 will vary as the photosensitive plate is illuminated by light of various colors at a given intensity and by light of various intensities of a given color.

Does the photoelectric effect prove that light is made of particles? Do interference experiments prove that light is composed of waves? (Is there a distinction between what something is and how it behaves?)

An electron and a proton travel at the same speed. Which has the greater momentum? Which has the longer wavelength?

One electron travels twice as fast as another. Which has the longer wavelength?

We don’t notice the wavelength of moving matter in our common experience. Is this because the wavelength is extraordinarily large or extraordinarily small?

Suppose that you lived in a hypothetical world in which you’d be knocked down by a single photon, in which matter would be so wavelike that it would be fuzzy and hard to grasp, and in which the uncertainty principle would impinge on simple measurements of position and speed in a laboratory, making results irreproducible. In such a world, discuss how Planck’s constant compares with the accepted value.

A friend says, “If an electron is not a particle, then it must be a wave.” What is your response? (Do you hear “either–or” statements like this often?)

What is a quantum of light called?