All Related Questions of Photons

Q: What does the wavelength of electromagnetic radiation represent? How is the

What does the wavelength of electromagnetic radiation represent? How is the wavelength of radiation related to the energy of the photons of the radiation?

Q: Consider the bright line spectrum of hydrogen shown in Fig. 11

Consider the bright line spectrum of hydrogen shown in Fig. 11.10. Which line in the spectrum represents photons with the highest energy? With the lowest energy?

Q: Because a given element’s atoms emit only certain photons of light,

Because a given element’s atoms emit only certain photons of light, only certain are occurring in those particular atoms.

Q: When a tube containing hydrogen atoms is energized by passing several thousand

When a tube containing hydrogen atoms is energized by passing several thousand volts of electricity into the tube, the hydrogen emits light that, when passed through a prism, resolves into the â...

Q: Explain what it means for an atom to be in an excited

Explain what it means for an atom to be in an excited state and what it means for an atom to be in its ground state. How does an excited atom return to its ground state? What is a photon? How is the w...

Q: Consider Compton scattering of a photon by a moving electron. Before

Consider Compton scattering of a photon by a moving electron. Before the collision the photon has wavelength λ and is moving in the +x-direction, and the electron is moving in the â...

Q: In what ways do photons resemble other particles such as electrons?

In what ways do photons resemble other particles such as electrons? In what ways do they differ? Do photons have mass? Do they have electric charge? Can they be accelerated? What mechanical properties...

Q: An electron and a positron are moving toward each other and each

An electron and a positron are moving toward each other and each has speed 0.500c in the lab frame. a. What is the kinetic energy of each particle? b. The e+ and e- meet head-on and annihilate. What...

Q: A 75-W light source consumes 75 W of electrical power

A 75-W light source consumes 75 W of electrical power. Assume all this energy goes into emitted light of wavelength 600 nm. a. Calculate the frequency of the emitted light. b. How many photons per s...

Q: A laser used to weld detached retinas emits light with a wavelength

A laser used to weld detached retinas emits light with a wavelength of 652 nm in pulses that are 20.0 ms in duration. The average power during each pulse is 0.600 W. a. How much energy is in each pul...

Q: The high-energy photons can undergo Compton scattering off electrons in

The high-energy photons can undergo Compton scattering off electrons in the tumor. The energy imparted by a photon is a maximum when the photon scatters straight back from the electron. In this proces...

Q: The probability of a photon interacting with tissue via the photoelectric effect

The probability of a photon interacting with tissue via the photoelectric effect or the Compton effect depends on the photon energy. Use Fig. P38.44 to determine the best description of how the photon...

Q: Higher-energy photons might be desirable for the treatment of certain

Higher-energy photons might be desirable for the treatment of certain tumors. Which of these actions would generate higher-energy photons in this linear accelerator? a. Increasing the number of elect...

Q: Nuclear fusion reactions at the center of the sun produce gamma-

Nuclear fusion reactions at the center of the sun produce gamma-ray photons with energies of about 1 MeV (106 eV). By contrast, what we see emanating from the sun’s surface are visible light photons w...

Q: To test the photon concept, you perform a Compton-scattering

To test the photon concept, you perform a Compton-scattering experiment in a research lab. Using photons of very short wavelength, you measure the wavelength λ′ of scatt...

Q: a. If the average frequency emitted by a 120-W

a. If the average frequency emitted by a 120-W light bulb is 5.00 * 1014 Hz and 10.0% of the input power is emitted as visible light, approximately how many visible-light photons are emitted per secon...

Q: The energy-level scheme for the hypothetical one electron element Searsium

The energy-level scheme for the hypothetical one electron element Searsium is shown in Fig. E39.25. The potential energy is taken to be zero for an electron at an infinite distance from the nucleus....

Q: In a set of experiments on a hypothetical one electron atom,

In a set of experiments on a hypothetical one electron atom, you measure the wavelengths of the photons emitted from transitions ending in the ground level (n = 1), as shown in the energy-level diagra...

Q: Using a mixture of CO2, N2, and sometimes He,

Using a mixture of CO2, N2, and sometimes He, CO2 lasers emit a wavelength of 10.6 mm. At power outputs of 0.100 kW, such lasers are used for surgery. How many photons per second does a CO2 laser deli...

Q: Pulsed dye lasers emit light of wavelength 585 nm in 0.

Pulsed dye lasers emit light of wavelength 585 nm in 0.45-ms pulses to remove skin blemishes such as birthmarks. The beam is usually focused onto a circular spot 5.0 mm in diameter. Suppose that the o...

Q: How many photons per second are emitted by a 7.50

How many photons per second are emitted by a 7.50-mW CO2 laser that has a wavelength of 10.6 µm?

Q: Photorefractive keratectomy (PRK) is a laser-based surgical procedure

Photorefractive keratectomy (PRK) is a laser-based surgical procedure that corrects near- and farsightedness by removing part of the lens of the eye to change its curvature and hence focal length. Thi...

Q: Figure 39.19a shows the energy levels of the sodium atom

Figure 39.19a shows the energy levels of the sodium atom. The two lowest excited levels are shown in columns labeled 2P3/2 and 2P1/2. Find the ratio of the number of atoms in a 2P3/2 state to the numb...

Q: a. What accelerating potential is needed to produce electrons of wavelength

a. What accelerating potential is needed to produce electrons of wavelength 5.00 nm? b. What would be the energy of photons having the same wavelength as these electrons? c. What would be the wavele...

Q: The star Betelgeuse has a surface temperature of 3000 K and is

The star Betelgeuse has a surface temperature of 3000 K and is 600 times the diameter of our sun. (If our sun were that large, we would be inside it!) Assume that it radiates like an ideal blackbody....

Q: What must be the temperature of an ideal blackbody so that photons

What must be the temperature of an ideal blackbody so that photons of its radiated light having the peak-intensity wavelength can excite the electron in the Bohr-model hydrogen atom from the ground le...

Q: A student asserts that a material particle must always have a speed

A student asserts that a material particle must always have a speed slower than that of light, and a massless particle must always move at exactly the speed of light. Is she correct? If so, how do mas...

Q: There is a certain probability that a single electron may simultaneously absorb

There is a certain probability that a single electron may simultaneously absorb two identical photons from a high-intensity laser. How would such an occurrence affect the threshold frequency and the e...

Q: A photon with wavelength λ = 0.1385 nm scatters from

A photon with wavelength λ = 0.1385 nm scatters from an electron that is initially at rest. What must be the angle between the direction of propagation of the incident and scattered photons if the spe...

Q: A laser produces light of wavelength 625 nm in an ultrashort pulse

A laser produces light of wavelength 625 nm in an ultrashort pulse. What is the minimum duration of the pulse if the minimum uncertainty in the energy of the photons is 1.0%?

Q: A pulsed dye laser emits light of wavelength 585 nm in 450

A pulsed dye laser emits light of wavelength 585 nm in 450-ms pulses. Because this wavelength is strongly absorbed by the hemoglobin in the blood, the method is especially effective for removing vario...

Q: Galaxies tend to be strong emitters of Lyman-α photons (

Galaxies tend to be strong emitters of Lyman-α photons (from the n = 2 to n = 1 transition in atomic hydrogen). But the intergalactic medium—the very thin gas between the galaxies— tends to absorb Lym...

Q: A large number of hydrogen atoms are in thermal equilibrium. Let

A large number of hydrogen atoms are in thermal equilibrium. Let n2/n1 be the ratio of the number of atoms in an n = 2 excited state to the number of atoms in an n = 1 ground state. At what temperatur...

Q: High-speed electrons are used to probe the interior structure of

High-speed electrons are used to probe the interior structure of the atomic nucleus. For such electrons the expression l = h/p still holds, but we must use the relativistic expression for momentum, p...

Q: Hydrogen atoms are placed in an external magnetic field. The protons

Hydrogen atoms are placed in an external magnetic field. The protons can make transitions between states in which the nuclear spin component is parallel and antiparallel to the field by absorbing or e...

Q: In a diagnostic x-ray procedure, 5.00 *

In a diagnostic x-ray procedure, 5.00 * 1010 photons are absorbed by tissue with a mass of 0.600 kg. The x-ray wavelength is 0.0200 nm. a. What is the total energy absorbed by the tissue? b. What is...

Q: Two equal-energy photons collide head-on and annihilate each

Two equal-energy photons collide head-on and annihilate each other, producing a µ+µ- pair. The muon mass is given in terms of the electron mass in Section 44.1. a. Calculate the maximum wavelength of...

Q: The hyperfine interaction in a hydrogen atom between the magnetic dipole moment

The hyperfine interaction in a hydrogen atom between the magnetic dipole moment of the proton and the spin magnetic dipole moment of the electron splits the ground level into two levels separated by 5...

Q: If the annihilation photons come from a part of the body that

If the annihilation photons come from a part of the body that is separated from the detector by 20 cm of tissue, what percentage of the photons that originally travelled toward the detector remains af...

Q: Suppose that positron–electron annihilations occur on the line 3 cm

Suppose that positron–electron annihilations occur on the line 3 cm from the center of the line connecting two detectors. Will the resultant photons be counted as having arrived at these detectors sim...

Q: One advantage of the quantum dot is that, compared to many

One advantage of the quantum dot is that, compared to many other fluorescent materials, excited states have relatively long lifetimes (10 ns). What does this mean for the spread in the energy of the p...

Q: Why might 123I be preferred for imaging over 131I? a

Why might 123I be preferred for imaging over 131I? a. The atomic mass of 123I is smaller, so the 123I particles travel farther through tissue. b. Because 123I emits only gamma-ray photons, the radia...

Q: In your research on new solid-state devices, you are

In your research on new solid-state devices, you are studying a solid-state structure that can be modeled accurately as an electron in a one-dimensional infinite potential well (box) of width L. In on...

Q: A lithium atom has three electrons, and the 2S1/2

A lithium atom has three electrons, and the 2S1/2 ground-state electron configuration is 1s22s. The 1s22p excited state is split into two closely spaced levels, 2P3/2 and 2P1/2, by the spin-orbit inte...

Q: A 60Co source with activity 2.6 * 10-4

A 60Co source with activity 2.6 * 10-4 Ci is embedded in a tumor that has mass 0.200 kg. The source emits g photons with average energy 1.25 MeV. Half the photons are absorbed in the tumor, and half e...

Q: A light bulb of 100W emits green light (wavelength of 500

A light bulb of 100W emits green light (wavelength of 500 nm photons are emitted from the light bulb in a second?

Q: A light bulb of 100W emits green light (wavelength of 500

A light bulb of 100W emits green light (wavelength of 500 nm). How many photons are emitted from the light bulb in a second?

Q: Given that Eg = 0.67 eV for germanium, find

Given that Eg = 0.67 eV for germanium, find the wavelength of peak solar response for the material. Do the photons at this wavelength have a lower or higher energy level?

Q: The resolving power of a microscope is proportional to the wavelength used

The resolving power of a microscope is proportional to the wavelength used. A resolution of 1.0 x 10-11 m (0.010 nm) would be required in order to “see” an atom. (a) If electrons were used (electron m...

Q: A 2.0 - kg object falls from a height of

A 2.0 - kg object falls from a height of 5.0 m to the ground. If the change in the object’s kinetic energy could be converted to visible light of wavelength 5.0 x 10-7 m, how many photons would be pro...

Q: A pulsed ruby laser emits light at 694.3 nm.

A pulsed ruby laser emits light at 694.3 nm. For a 14.0 - ps pulse containing 3.00 J of energy, find (a) The physical length of the pulse as it travels through space and (b) The number of photons in i...

Q: (a) Lightning produces a maximum air temperature on the order

(a) Lightning produces a maximum air temperature on the order of 104 K, whereas (b) A nuclear explosion produces a temperature on the order of 107 K. Use Wien’s displacement law to find the order of m...

Q: Suppose a star with radius 8.50 x 108 m has

Suppose a star with radius 8.50 x 108 m has a peak wavelength of 685 nm in the spectrum of its emitted radiation. (a) Find the energy of a photon with this wavelength. (b) What is the surface temperat...

Q: The threshold of dark - adapted (scotopic) vision is 4

The threshold of dark - adapted (scotopic) vision is 4.0 x 10-11 W/m2 at a central wavelength of 5.00 x 102 nm. If light with this intensity and wavelength enters the eye when the pupil is open to its...

Q: The work function for zinc is 4.31 eV.

The work function for zinc is 4.31 eV. (a) Find the cutoff wavelength for zinc. (b) What is the lowest frequency of light incident on zinc that releases photoelectrons from its surface? (c) If photons...

Q: The work function for platinum is 6.35 eV.

The work function for platinum is 6.35 eV. (a) Convert the value of the work function from electron volts to joules. (b) Find the cutoff frequency for platinum. (c) What maximum wavelength of light in...

Q: What is the energy in joules associated with photons that have a

What is the energy in joules associated with photons that have a wavelength matching that of the color blue in the visible spectrum? Repeat part (a) for the color red. Do the results confirm the fact...

Q: Many radioisotopes have important industrial, medical, and research applications.

Many radioisotopes have important industrial, medical, and research applications. One of these is 60Co, which has a half - life of 5.2 years and decays by the emission of a beta particle (energy 0.31...

Q: A neutral pion at rest decays into two photons according to

A neutral pion at rest decays into two photons according to π0 ( ( + ( Find the energy, momentum, and frequency of each photon.

Q: The fracture pattern of glass usually has: A) Radial

The fracture pattern of glass usually has: A) Radial lines. B) Concentric lines. C) Radial and concentric lines. D) Directional lines. 32) If glass cannot be physically pieced together, then the cont...

Q: A hydrogen atom has an electron in the n = 5 level

A hydrogen atom has an electron in the n = 5 level. (a) If the electron returns to the ground state by emitting radiation, what is the minimum number of photons that can be emitted? (b)What is the m...

Q: (a) Find the energies of the first four levels of

(a) Find the energies of the first four levels of doubly ionized lithium (Li2+), starting with n = 1. (b) What are the energies of the photons emitted or absorbed when the electron makes a transition...

Q: A positron emission tomography (PET) scanner detects 511 keV photons

A positron emission tomography (PET) scanner detects 511 keV photons emitted when positrons and electrons annihilate each other. What is the wavelength of the photons?

Q: A muon and an antimuon, each with a mass that is

A muon and an antimuon, each with a mass that is 207 times greater than an electron, were at rest when they annihilated and produced two photons of equal energy. What is the wavelength of each of the...

Q: A photoconductor (see Conceptual Question 13) allows charge to flow

A photoconductor (see Conceptual Question 13) allows charge to flow freely when photons of wavelength 640 nm or less are incident on it. What is the band gap for this photoconductor?

Q: If meat is irradiated with 2000.0 Gy of x-

If meat is irradiated with 2000.0 Gy of x-rays, most of the bacteria are killed and the shelf life of the meat is greatly increased. (a) How many 100.0 keV photons must be absorbed by a 0.30 kg steak...

Q: In gamma-ray astronomy, the existence of positrons (e

In gamma-ray astronomy, the existence of positrons (e+) can be inferred by characteristic gamma-ray photons that are emitted when a positron and an electron (e−) annihilate. For simplicity, assume tha...

Q: An owl has good night vision because its eyes can detect a

An owl has good night vision because its eyes can detect a light intensity as faint as 5.0 × 10−13 W/m2. What is the minimum number of photons per second that an owl eye can detect if its pupil has a...

Q: The output power of a laser pointer is about 1 mW.

The output power of a laser pointer is about 1 mW. (a) What are the energy and momentum of one laser photon if the laser wavelength is 670 nm? (b) How many photons per second are emitted by the lase...

Q: An electron is confined to a one-dimensional box of length

An electron is confined to a one-dimensional box of length L. When the electron makes a transition from its first excited state to the ground state, it emits a photon of energy 0.20 eV. (a) What is t...

Q: What process becomes especially important for photons with energies in excess of

What process becomes especially important for photons with energies in excess of 1.02 MeV?

Q: Explain why the annihilation of an electron and a positron creates a

Explain why the annihilation of an electron and a positron creates a pair of photons rather than a single photon.

Q: An experiment shines visible light on a target and measures the wavelengths

An experiment shines visible light on a target and measures the wavelengths of light scattered at different angles. Would the experiment show that the scattered photons are Compton-shifted? Explain.

Q: One of the first signs of sunburn is the reddening of the

One of the first signs of sunburn is the reddening of the skin (called erythema). As a very rough rule of thumb, erythema occurs if 13 mJ of ultraviolet light of approximately 300 nm wavelength (refer...

Q: A hydrogen atom in its ground state is immersed in a continuous

A hydrogen atom in its ground state is immersed in a continuous spectrum of ultraviolet light with wavelengths ranging from 96 nm to 110 nm. After absorbing a photon, the atom emits one or more photon...

Q: When photons with a wavelength of 120.0 nm are incident

When photons with a wavelength of 120.0 nm are incident on a metal, electrons are ejected that can be stopped with a stopping potential of 6.00 V. (a) What stopping potential is needed when the photo...

Q: A surgeon is attempting to correct a detached retina by using a

A surgeon is attempting to correct a detached retina by using a pulsed laser. (a) If the pulses last for 20.0 ms and if the output power of the laser is 0.500 W, how much energy is in each pulse? (b...

Q: Isolated atoms (or atoms in a dilute gas) radiate photons

Isolated atoms (or atoms in a dilute gas) radiate photons at discrete energies characteristic of that atom. In dense matter, the spectrum radiated is quasi-continuous. Why doesn’t the same thing happe...

Q: ɦ Photons of energy E = 4.000 keV undergo Compton

ɦ Photons of energy E = 4.000 keV undergo Compton scattering. What is the largest possible change in photon energy, measured as a fraction of the incident photon's energy (E − E′)/E?

Q: A 100 W incandescent lightbulb radiates visible light at a rate of

A 100 W incandescent lightbulb radiates visible light at a rate of about 10 W; the rest of the EM radiation is mostly infrared. Assume that the lightbulb radiates uniformly in all directions. Under id...

Q: Nuclei in a radium-226 radioactive source emit photons whose energy

Nuclei in a radium-226 radioactive source emit photons whose energy is 186 keV. These photons are scattered by the electrons in a metal target; a detector measures the energy of the scattered photons...

Q: Figure 29.7 is an energy level diagram for 208Tl.

Figure 29.7 is an energy level diagram for 208Tl. What are the energies of the photons emitted for the six transitions shown?

Q: An FM radio station broadcasts at a frequency of 89.3

An FM radio station broadcasts at a frequency of 89.3 MHz. The power radiated from the antenna is 50.0 kW. (a) What is the energy in electron-volts of each photon radiated by the antenna? (b) How ma...

Q: An incident beam of photons is scattered through 100.0°;

An incident beam of photons is scattered through 100.0°; the wavelength of the scattered photons is 124.65 pm. What is the wavelength of the incident photons?

Q: A 220 W laser fires a 0.250 ms pulse of

A 220 W laser fires a 0.250 ms pulse of light with a wavelength of 680 nm. (a) What is the energy of each photon in the laser beam? (b) How many photons are in this pulse?

Q: A 640 nm laser emits a 1.0 s pulse in

A 640 nm laser emits a 1.0 s pulse in a beam with a diameter of 1.5 mm. The rms electric field of the pulse is 120 V/m. How many photons are emitted per second?

Q: A Compton scattering experiment is performed using an aluminum target. The

A Compton scattering experiment is performed using an aluminum target. The incident photons have wavelength λ. The scattered photons have wavelengths λ′ and energies E that depend on the scattering an...

Q: Photons of wavelength 350 nm are incident on a metal plate in

Photons of wavelength 350 nm are incident on a metal plate in a photocell, and electrons are ejected. A stopping potential of 1.10 V is able to just prevent any of the ejected electrons from reaching...

Q: The photoelectric effect is studied using a tungsten target. The work

The photoelectric effect is studied using a tungsten target. The work function of tungsten is 4.5 eV. The incident photons have energy 4.8 eV. (a) What is the threshold frequency? (b) What is the st...

Q: 1. An electron, passing close to a target nucleus,

1. An electron, passing close to a target nucleus, slows and radiates away some of its energy. What is this process called? (a) Compton effect (b) photoelectric effect (c) bremsstrahlung (d) blackbody...

Q: Photoelectric experiments are performed with five different metals. Given the work

Photoelectric experiments are performed with five different metals. Given the work function of the metal ϕ and the energy of the incident photons E, rank the experiments in order of the stopping poten...

Q: A thin aluminum target is illuminated with photons of wavelength λ.

A thin aluminum target is illuminated with photons of wavelength λ. A detector is placed at 90.0° to the direction of the incident photons. The scattered photons detected are found to have half the en...

Q: A 200 W infrared laser emits photons with a wavelength of 2

A 200 W infrared laser emits photons with a wavelength of 2.0 × 10−6 m, and a 200 W ultraviolet light emits photons with a wavelength of 7.0 × 10−8 m. (a) Which has greater energy, a single infrared...

Q: Photons with a wavelength of 400 nm are incident on an unknown

Photons with a wavelength of 400 nm are incident on an unknown metal, and electrons are ejected from the metal. However, when photons with a wavelength of 700 nm are incident on the metal, no electron...

Q: A neutral pion of (rest) mass m and (relativistic

A neutral pion of (rest) mass m and (relativistic) momentum / decays into two photons. One of the photons is emitted in the same direction as the original pion, and the other in the opposite direction...

Q: In a pair annihilation experiment, an electron (mass m)

In a pair annihilation experiment, an electron (mass m) with momentum pe hits a positron (same mass, but opposite charge) at rest. They annihilate, producing two photons. (Why couldn’t they produce ju...