A neutral pion at rest decays into two photons. Find the energy, frequency, and wavelength of each photon. In which part of the electromagnetic spectrum does each photon lie? (Use the pion mass given in terms of the electron mass in Section 44.1.)
> An electron in a onedimensional box has groundstate energy 2.00 eV. What is the wavelength of the photon absorbed when the electron makes a transition to the second excited state?
> A certain atom requires 3.0 eV of energy to excite an electron from the ground level to the first excited level. Model the atom as an electron in a box and find the width L of the box.
> Figure 40.17 shows the scanning tunneling microscope image of 48 iron atoms placed on a copper surface, the pattern indicating the density of electrons on the copper surface. What can you infer about the potential-energy function inside the circle of iro
> A student remarks that the relationship of ray optics to the more general wave picture is analogous to the relationship of Newtonian mechanics, with well-defined particle trajectories, to quantum mechanics. Comment on this remark.
> When a hydrogen atom undergoes a transition from the n = 2 to the n = 1 level, a photon with λ = 122 nm is emitted. a. If the atom is modeled as an electron in a onedimensional box, what is the width of the box in order for the n = 2 to n = 1 transitio
> Find the width L of a onedimensional box for which the groundstate energy of an electron in the box equals the absolute value of the ground state of a hydrogen atom.
> A proton is in a box of width L. What must the width of the box be for the groundlevel energy to be 5.0 MeV, a typical value for the energy with which the particles in a nucleus are bound? Compare your result to the size of a nucleus—that is, on the ord
> a. Find the lowest energy level for a particle in a box if the particle is a billiard ball (m = 0.20 kg) and the box has a width of 1.3 m, the size of a billiard table. (Assume that the billiard ball slides without friction rather than rolls; that is, ig
> Deuterons in a cyclotron travel in a circle with radius 32.0 cm just before emerging from the dees. The frequency of the applied alternating voltage is 9.00 MHz. Find a. the magnetic field and b. the kinetic energy and speed of the deuterons upon emerg
> An electron with a total energy of 30.0 GeV collides with a stationary positron. a. What is the available energy? b. If the electron and positron are accelerated in a collider, what total energy corresponds to the same available energy as in part (a)?
> The starship Enterprise, of television and movie fame, is powered by combining matter and antimatter. If the entire 400-kg antimatter fuel supply of the Enterprise combines with matter, how much energy is released? How does this compare to the U.S. yearl
> Estimate the range of the force mediated by an ω0 meson that has mass 783 MeV/c2.
> For the nuclear reaction given in Eq. (44.2) assume that the initial kinetic energy and momentum of the reacting particles are negligible. Calculate the speed of the α particle immediately after it leaves the reaction region.
> A proton and an antiproton annihilate, producing two photons. Find the energy, frequency, and wavelength of each photon a. if the p and p are initially at rest and b. if the p and p collide head-on, each with an initial kinetic energy of 620 MeV.
> In classical (Newtonian) mechanics, the total energy E of a particle can never be less than the potential energy U because the kinetic energy K cannot be negative. Yet in barrier tunneling (see Section 40.4) a particle passes through regions where E is l
> Calculate the reaction energy Q (in MeV) for the nucleosynthesis reaction 6 12
> The 2.728-K blackbody radiation has its peak wavelength at 1.062 mm. What was the peak wavelength at t = 700,000 y when the temperature was 3000 K?
> Calculate the energy (in MeV) released in the triple alpha process 3 4He → 12C.
> Calculate the reaction energy Q (in MeV) for the reaction e- + p → n + ve. Is this reaction endoergic or exoergic?
> The definition of the redshift z is given in Example 44.8. a. Show that Eq. (44.13) can be written as 1 + z =([1 + β]/[1 – β])1/2 , where β = v/c. b. The observed redshift for a certain galaxy is z
> A galaxy in the constellation Pisces is 5210 Mly from the earth. a. Use the Hubble law to calculate the speed at which this galaxy is receding from earth. b. What redshifted ratio λ0/λS is expected for light from this galaxy?
> In an experiment done in a laboratory on the earth, the wavelength of light emitted by a hydrogen atom in the n = 4 to n = 2 transition is 486.1 nm. In the light emitted by the quasar 3C273 (see Problem 36.60), this spectral line is redshifted to 563.9 n
> The spectrum of the sodium atom is detected in the light from a distant galaxy. a. If the 590.0-nm line is redshifted to 658.5 nm, at what speed is the galaxy receding from the earth? b. Use the Hubble law to calculate the distance of the galaxy from th
> Section 44.5 states that current experiments show that the mass of the Higgs boson is about 125 GeV/c2. What is the ratio of the mass of the Higgs boson to the mass of a proton?
> A positive pion at rest decays into a positive muon and a neutrino. a. Approximately how much energy is released in the decay? (Assume the neutrino has zero rest mass. Use the muon and pion masses given in terms of the electron mass in Section 44.1.) b
> Figure 40.15a shows that the higher the energy of a bound state for a finite potential well, the more the wave function extends outside the well (into the intervals x L). Explain why this happens. From Figure 40.15a 40.15 (a) Wave functions for th
> Given that each particle contains only combinations of u, d, s, u, d, and s, use the method of Example 44.7 to deduce the quark content of a. a particle with charge +e, baryon number 0, and strangeness +1; b. a particle with charge +e, baryon number -1
> What is the total kinetic energy of the decay products when an upsilon particle at rest decays to τ+ + τ- ?
> Determine the electric charge, baryon number, strangeness quantum number, and charm quantum number for the following quark combinations: a. uds; b. cu; c. ddd; and d. dc. Explain your reasoning.
> Determine the electric charge, baryon number, strangeness quantum number, and charm quantum number for the following quark combinations: a. uus, b. cs, c. ddu, and d. cb.
> In which of the following reactions or decays is strangeness conserved? In each case, explain your reasoning. a. K+→ µ+ + vµ; b. n + K+→ p + π0; c. K+ + K-→ π 0 + π 0; d. p + K- →Λ0 + π 0.
> Which of the following reactions obey the conservation of baryon number? a. p + p → p + e+; b. p + n → 2e+ + e-; c. p → n + e- + ve; d. p + p → 2γ.
> In which of the following decays are the three lepton numbers conserved? In each case, explain your reasoning. a. µ- → e- + ve + vµ; b. τ- → e- + ve + vτ; c. π+ → e+ + γ; d. n → p + e- + ve .
> The discovery of the Ω- particle helped confirm GellMann’s eightfold way. If an Ω decays into a Λ0 and a K-, what is the total kinetic energy of the decay products?
> If a Σ+ at rest decays into a proton and a π0, what is the total kinetic energy of the decay products?
> Table 44.3 shows that a Σ0 decays into a Λ0 and a photon. a. Calculate the energy of the photon emitted in this decay, if the Λ0 is at rest. b. What is the magnitude of the momentum of the photon? Is it reasonable to ignore the final momentum and kinet
> It is stated in Section 40.3 that a finite potential well always has at least one bound level, no matter how shallow the well. Does this mean that as U0 0, E1 0? Does this violate the Heisenberg uncertainty principle? Explain.
> 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 the photons for this to occur. If the photons have th
> What is the mass (in kg) of the Z0? What is the ratio of the mass of the Z0 to the mass of the proton?
> How much energy is released when a µ- muon at rest decays into an electron and two neutrinos? Neglect the small masses of the neutrinos.
> A K+ meson at rest decays into two π mesons. a. What are the allowed combinations of π0, π+, and π- as decay products? b. Find the total kinetic energy of the π mesons.
> You work for a start-up company that is planning to use antiproton annihilation to produce radioactive isotopes for medical applications. One way to produce antiprotons is by the reaction p + p → p + p + p + p in proton-proton collisions. a. You first c
> In Example 44.3 it was shown that a proton beam with an 800-GeV beam energy gives an available energy of 38.7 GeV for collisions with a stationary proton target. a. You are asked to design an upgrade of the accelerator that will double the available ene
> Calculate the minimum beam energy in a proton-proton collider to initiate the p + p → p + p + η0 reaction. The rest energy of the h0 is 547.3 MeV (see Table 44.3). From Table 44.3 TABLE 44.3 Some Hadrons and Th
> a. what is the speed of the proton that has total energy 1000 GeV? b. What is the angular frequency ω of a proton with the speed calculated in part (a) in a magnetic field of 4.00 T? Use both the nonrelativistic Eq. (44.7) and the correct rel
> Let ωnr be the nonrelativistic cyclotron angular frequency given by Eq. (44.7), and let ωr be the corresponding relativistic value, ωr =(|q|B/m) 1−
> a. A high-energy beam of alpha particles collides with a stationary helium gas target. What must the total energy of a beam particle be if the available energy in the collision is 16.0 GeV? b. If the alpha particles instead interact in a colliding-beam
> Compare the wave functions for the first three energy levels for a particle in a box of width L (see Fig. 40.12a) to the corresponding wave functions for a finite potential well of the same width (see Fig. 40.15a). How does the wavelength in the interval
> The magnetic field in a cyclotron that accelerates protons is 1.70 T. a. How many times per second should the potential across the dees reverse? (This is twice the frequency of the circulating protons.) b. The maximum radius of the cyclotron is 0.250 m
> A photon with a wavelength of 3.50 * 10-13 m strikes a deuteron, splitting it into a proton and a neutron. a. Calculate the kinetic energy released in this interaction. b. Assuming the two particles share the energy equally, and taking their masses to
> An alpha particle is strongly bound. The 6 12
> Calculate a. the total binding energy and b. the binding energy per nucleon of 12C. c. What percent of the rest mass of this nucleus is its total binding energy?
> The most common isotope of uranium, 92 238
> The most common isotope of boron is 5 11
> Consider the nuclear reaction 14 28
> Consider the nuclear reaction 2 4
> The United States uses about 1.4 * 1019 J of electrical energy per year. If all this energy came from the fission of 235U, which releases 200 MeV per fission event, a. how many kilograms of 235U would be used per year, and b. how many kilograms of uran
> A particle is confined to a finite potential well in the region 0 < x < L. How does the area under the graph of Ψ 2 in the region 0 < x < L compare to the total area under the graph of Ψ 2 when including all possible x?
> At the beginning of Section 43.7 the equation of a fission process is given in which 235U is struck by a neutron and undergoes fission to produce 144Ba, 89Kr, and three neutrons. The measured masses of these isotopes are 235.043930 u (235U), 143.922953 u
> Calculate the energy released in the fusion reaction 2 3
> Consider the nuclear reaction 1 2
> Calculate the reaction energy Q for the reaction p + 1 3
> The nuclei 5 11
> 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 the equivalent dose in rem?
> In an industrial accident a 65-kg person receives a lethal whole-body equivalent dose of 5.4 Sv from x rays. a. What is the equivalent dose in rem? b. What is the absorbed dose in rad? c. What is the total energy absorbed by the person’s body? How doe
> A 67-kg person accidentally ingests 0.35 Ci of tritium. a. Assume that the tritium spreads uniformly throughout the body and that each decay leads on the average to the absorption of 5.0 keV of energy from the electrons emitted in the decay. The half-li
> It has become popular for some people to have yearly whole-body scans (CT scans, formerly called CAT scans) using x rays, just to see if they detect anything suspicious. A number of medical people have recently questioned the advisability of such scans,
> Food is often irradiated with either x rays or electron beams to help prevent spoilage. A low dose of 5–75 kilorads (krad) helps to reduce and kill inactive parasites, a medium dose of 100–400 krad kills microorganisms
> In Fig. 40.12b, the probability function is zero at the points x = 0 and x = L, the “walls” of the box. Does this mean that the particle never strikes the walls? Explain. From Fig. 40.12b (b) \W»F n = 3 n = 2 n =
> A person exposed to fast neutrons receives a radiation dose of 300 rem on part of his hand, affecting 25 g of tissue. The RBE of these neutrons is 10. a. How many rad did he receive? b. How many joules of energy did he receive? c. Suppose the person r
> A nuclear chemist receives an accidental radiation dose of 5.0 Gy from slow neutrons (RBE = 4.0). What does she receive in rad, rem, and J/kg?
> If a person’s entire body is exposed to 5.0 J / kg of x rays, death usually follows within a few days. a. Express this lethal radiation dose in Gy, rad, Sv, and rem. b. How much total energy does a 70.0-kg person absorb from such a dose? c. If the 5.0
> a. If a chest x ray delivers 0.25 mSv to 5.0 kg of tissue, how many total joules of energy does this tissue receive? b. Natural radiation and cosmic rays deliver about 0.10 mSv per year at sea level. Assuming an RBE of 1, how many rem and rads is this d
> At an archeological site, a sample from timbers containing 500 g of carbon provides 2690 decays>min. What is the age of the sample?
> 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 emitting a photon. What magnetic-field magnitude is req
> The radioactive nuclide 199Pt has a half-life of 30.8 minutes. A sample is prepared that has an initial activity of 7.56 * 1011 Bq. a. How many 199Pt nuclei are initially present in the sample? b. How many are present after 30.8 minutes? What is the ac
> A radioactive isotope has a half-life of 43.0 min. At t = 0 its activity is 0.376 Ci. What is its activity at t = 2.00 h?
> Measurements on a certain isotope tell you that the decay rate decreases from 8318 decays/min to 3091 decays/min in 4.00 days. What is the half-life of this isotope?
> As a health physicist, you are being consulted about a spill in a radiochemistry lab. The isotope spilled was 400 µCi of 131Ba, which has a half-life of 12 days. a. What mass of 131Ba was spilled? b. Your recommendation is to clear the lab until the ra
> For a particle in a finite potential well, is it correct to say that each bound state of definite energy is also a state of definite wavelength? Is it a state of definite momentum? Explain.
> The unstable isotope 40K is used for dating rock samples. Its half-life is 1.28 * 109 y. a. How many decays occur per second in a sample containing 1.63 * 10-6 g of 40K? b. What is the activity of the sample in curies?
> Radioactive isotopes are often introduced into the body through the bloodstream. Their spread through the body can then be monitored by detecting the appearance of radiation in different organs. One such tracer is 131I, a β- emitter with a half-life of 8
> A 12.0-g sample of carbon from living matter decays at the rate of 184 decays/minute due to the radioactive 14C in it. What will be the decay rate of this sample in a. 1000 years and b. 50,000 years?
> In many cases, prostate cancer is treated by implanting 60 to 100 small seeds of radioactive material into the tumor. The energy released from the decays kills the tumor. One isotope that is used (there are others) is palladium (103Pd)), with a half-life
> The common isotope of uranium, 238U, has a half life of 4.47 * 109 years, decaying to 234Th by alpha emission. a. What is the decay constant? b. What mass of uranium is required for an activity of 1.00 curie? c. How many alpha particles are emitted pe
> Radioactive isotopes used in cancer therapy have a “shelf-life,” like pharmaceuticals used in chemotherapy. Just after it has been manufactured in a nuclear reactor, the activity of a sample of 60Co is 5000 Ci. When its activity falls below 3500 Ci, it i
> Neutrons are placed in a magnetic field with magnitude 2.30 T. a. What is the energy difference between the states with the nuclear spin angular momentum components parallel and antiparallel to the field? Which state is lower in energy: the one with its
> If a 6.13-g sample of an isotope having a mass number of 124 decays at a rate of 0.350 Ci, what is its half-life?
> Tritium ( 1 3
> a. Calculate the energy released by the electron-capture decay of 27 57
> For a particle confined to an infinite square well, is it correct to say that each state of definite energy is also a state of definite wavelength? Is it also a state of definite momentum? Explain. (Hint: Remember that momentum is a vector.)
> Analysis of the photon absorption spectrum of a diatomic molecule shows that the vibrational energy levels for small values of n are very nearly equally spaced but the levels for large n are not equally spaced. Discuss the reason for this observation. Do
> The moment of inertia for an axis through the center of mass of a diatomic molecule calculated from the wavelength emitted in an l = 19 l = 18 transition is different from the moment of inertia calculated from the wavelength of the photon emitted
> Why does tunneling limit the miniaturization of MOSFETs?
> The saturation current IS for a p-n junction, Eq. (42.22), depends strongly on temperature. Explain why. From Eq. (42.22): Saturation current - Voltage -Absolute temperature Current through· a p-n junction *I='Is(e•V/kT 1) Boltzmann constant Magnit
> The electrical conductivities of most metals decrease gradually with increasing temperature, but the intrinsic conductivity of semiconductors always increases rapidly with increasing temperature. What causes the difference?
> A student asserts that silicon and germanium become good insulators at very low temperatures and good conductors at very high temperatures. Do you agree? Explain your reasoning.
> The bonding of gallium arsenide (GaAs) is said to be 31% ionic and 69% covalent. Explain.
> Ionic crystals are often transparent, whereas metallic crystals are always opaque. Why?
> Individual atoms have discrete energy levels, but certain solids (which are made up of only individual atoms) show energy bands and gaps. What causes the solids to behave so differently from the atoms of which they are composed?
