New Semester Started Get 50% OFF Study Help! --h --m --s Claim Now

Question Answers

Textbooks

Find textbooks, questions and answers

Oops, something went wrong!

Change your search query and then try again

Result Not Found

Books FREE
Study Help
Tutors
AI Study Planner NEW
Sell Books

Search
Sign In
Register

study help
physics
university physics

University Physics with Modern Physics 14th edition Hugh D. Young, Roger A. Freedman - Solutions

Why can’t an electron decay to two photons? To two neutrinos?
According to the standard model of the fundamental particles, what are the similarities between baryons and leptons? What are the most important differences?
According to the standard model of the fundamental particles, what are the similarities between quarks and leptons? What are the most important differences?
The quark content of the neutron is udd.(a) What is the quark content of the antineutron? Explain your reasoning.(b) Is the neutron its own antiparticle? Why or why not?(c) The quark content of the ψ is cc̅. Is the ψ its own antiparticle? Explain your reasoning.
Does the universe have a center? Explain
Does it make sense to ask, “If the universe is expanding, what is it expanding into?”
Assume that the universe has an edge. Placing yourself at that edge in a thought experiment, explain why this assumption violates the cosmological principle.
Explain why the cosmological principle requires that H0 must have the same value everywhere in space, but does not require that it be constant in time.
Calculate the minimum beam energy in a proton-proton collider to initiate the p + p †’ p + p + Î·0 reaction. The rest energy of the Î·0is 547.3 MeV (see Table 44.3).Table 44.3 Some Hadrons and Their Properties Typical Decay Modes Charge Ratio, Baryon Number,
A K+ meson at rest decays into two π mesons.(a) What are the allowed combinations of π0, πp+, and π- as decay products?(b) Find the total kinetic energy of the π mesons.
A proton and an antiproton collide head-on with equal kinetic energies. Two γ rays with wavelengths of 0.720 fm are produced. Calculate the kinetic energy of the incident proton.
Calculate the reaction energy Q (in MeV) for the nucleosynthesis reaction 126C + 42He → 168OIs this reaction endoergic or exoergic?
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?
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 simultaneously?(a) No, because the time difference between their arrivals is 100 ms;(b) No, because
What is the energy of each photon produced by positron– electron annihilation?(a) 1/2mev2, where v is the speed of the emitted positron;(b) mev2;(c) ½ mec2;(d) mec2.
Use the band model to explain how it is possible for some materials to undergo a semiconductor-to-metal transition as the temperature or pressure varies.
An isolated zinc atom has a ground-state electron configuration of filled 1s, 2s, 2p, 3s, 3p, and 4s subshells. How can zinc be a conductor if its valence subshell is full?
The assumptions of the free-electron model of metals may seem contrary to reason, since electrons exert powerful electric forces on each other. Give some reasons why these assumptions actually make physical sense.
Why are materials that are good thermal conductors also good electrical conductors? What kinds of problems does this pose for the design of appliances such as clothes irons and electric heaters? Are there materials that do not follow this general rule?
What is the essential characteristic for an element to serve as a donor impurity in a semiconductor such as Si or Ge? For it to serve as an acceptor impurity? Explain.
There are several methods for removing electrons from the surface of a semiconductor. Can holes be removed from the surface? Explain.
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 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?
How could you make compensated silicon that has twice as many acceptors as donors?
The saturation current IS for a p-n junction, Eq. (42.22), depends strongly on temperature. Explain why.Eq.42.22 - Voltage Saturation current Absolute temperature Current through- a p-n junction I = Is(eev/kT Magnitude of electron charge Boltzmann constant e = 2.71828"
Why does tunneling limit the miniaturization of MOSFETs?
(a) Suppose a piece of very pure germanium is to be used as a light detector by observing, through the absorption of photons, the increase in conductivity resulting from generation of electron–hole pairs. If each pair requires 0.67 eV of energy, what is the maximum wavelength that can be
The binding energy of a potassium chloride molecule (KCl) is 4.43 eV. The ionization energy of a potassium atom is 4.3 eV, and the electron affinity of chlorine is 3.6 eV. Use these data to estimate the equilibrium separation between the two atoms in the KCl molecule. Explain why your result is
The sensitivity of a diode thermometer depends on how much the voltage changes for a given temperature change, with the current remaining constant. What is the sensitivity for this diode thermometer, operated at 100 mA, for a temperature change from 25°C to 150°C?(a) +0.2 mV/°C;(b) +2.0
Which statement best explains the temperature dependence of the current€“voltage characteristics that the graph shows? At higher temperatures:(a) The band gap is larger, so the electron hole pairs have more energy, which causes the current at a given voltage to be larger.(b) More
If the voltage rather than the current is kept constant, what happens as the temperature increases from 25°C to 150°C?(a) At first the current increases, then it decreases.(b) The current increases.(c) The current decreases, eventually approaching zero.(d) The current does not change unless
Neutrons have a magnetic dipole moment and can undergo spin flips by absorbing electromagnetic radiation. Why, then, are protons rather than neutrons used in MRI of body tissues? (See Fig. 43.1.)Fig.43.1 (a) Random spin of |hydrogen protons A brief radio signal causes the spins to flip orientation.
How many protons and how many neutrons are there in a nucleus of the most common isotope of(a) Silicon, 2814Si;(b) Rubidium, 8537Rb;(c) Thallium, 20581Tl?
In Eq. (43.11), as the total number of nucleons becomes larger, the importance of the second term in the equation decreases relative to that of the first term. Does this make physical sense? Explain.Eq.43.11 Z(Z – 1) (A – 2z)2 Ев 3 СА - САР3 — С3- C4- + C;A^4/3 A/3
Why aren’t the masses of all nuclei integer multiples of the mass of a single nucleon?
The only two stable nuclides with more protons than neutrons are 11H and 23He. Why is Z > N so uncommon?
What are the six known elements for which Z is a magic number? Discuss what properties these elements have as a consequence of their special values of Z.
The binding energy per nucleon for most nuclides doesn€™t vary much (see Fig. 43.2). Is there similar consistency in the atomic energy of atoms, on an €œenergy per electron€ basis? If so, why? If not, why not?Fig.43.2 ER/A (MeV/nucleon) Ni 238U 92 {He The curve
Heavy, unstable nuclei usually decay by emitting an a or a b particle. Why don’t they usually emit a single proton or neutron?
As stars age, they use up their supply of hydrogen and eventually begin producing energy by a reaction that involves the fusion of three helium nuclei to form a carbon nucleus. Would you expect the interiors of these old stars to be hotter or cooler than the interiors of younger stars? Explain.
An alpha particle is strongly bound. The 126C nucleus might be modeled as a composite of three alpha particles. Compare the binding energy of 126C with three times the binding energy of an alpha particle. Which of these quantities is larger, and why might this be so?
Since lead is a stable element, why doesn€™t the238U decay series shown in Fig. 43.7 stop at lead,214Pb?Fig.43.7 146 238U 4.47 x 10° y 145 234Th 144 24.10 d 143 234Pa 70s 142 234U 2.46 x 10 y 141 140 230TH 7.54 x 104 139 138 226Ra 1600 y 137 136 222Rn 3.82 d 135 134 218Po 3.10 m 133 a
In the238U decay series shown in Fig. 43.7, some nuclides in the series are found much more abundantly in nature than others, even though every238U nucleus goes through every step in the series before finally becoming206Pb. Why don??t the intermediate nuclides all have the same
Compared to a particles with the same energy, b particles can much more easily penetrate through matter. Why is this?
In a nuclear decay equation, why can we represent an electron as -10β-? What are the equivalent representations for a positron, a neutrino, and an antineutrino?
Why is the alpha, beta, or gamma decay of an unstable nucleus unaffected by the chemical situation of the atom, such as the nature of the molecule or solid in which it is bound? The chemical situation of the atom can, however, have an effect on the half-life in electron capture. Why is this?
In the process of internal conversion, a nucleus decays from an excited state to a ground state by giving the excitation energy directly to an atomic electron rather than emitting a gamma-ray photon. Why can this process also produce x-ray photons?
One problem in radiocarbon dating of biological samples, especially very old ones, is that they can easily be contaminated with modern biological material during the measurement process. What effect would such contamination have on the estimated age? Why is such contamination a more serious problem
The most common radium isotope found on earth, 226Ra, has a half-life of about 1600 years. If the earth was formed well over 109 years ago, why is there any radium left now?
Fission reactions occur only for nuclei with large nucleon numbers, while exoergic fusion reactions occur only for nuclei with small nucleon numbers. Why is this?
When a large nucleus splits during nuclear fission, the daughter nuclei of the fission fly apart with enormous kinetic energy. Why does this happen?
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?
At an archeological site, a sample from timbers containing 500 g of carbon provides 2690 decays/min. What is the age of the sample?
Calculate the reaction energy Q for the reactionIs this reaction exoergic or endoergic? p + H-H + fH.
Calculate the mass defect for the β+ decay of 116C. Is this decay energetically possible? Why or why not? The atomic mass of 116C is 11.011434 u.
In the reaction that produces 123I, is there a minimum kinetic energy the protons need to make the reaction go?(a) No, because the proton has a smaller mass than the neutron.(b) No, because the total initial mass is smaller than the total final mass.(c) Yes, because the proton has a smaller mass
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 radiation dose to the body is lower with that isotope.(c) The beta particles emitted by 131I can leave the
Speeds of molecules in a gas vary with temperature, whereas speeds of electrons in the conduction band of a metal are nearly independent of temperature. Why are these behaviors so different?
Ionic crystals are often transparent, whereas metallic crystals are always opaque. Why?
What factors determine whether a material is a conductor of electricity or an insulator? Explain.
The average kinetic energy of an idealgas atom or molecule is 3/2 kT, where T is the Kelvin temperature (Chapter 18). The rotational inertia of the H2 molecule is 4.6 × 10-48 kg ∙ m2. What is the value of T for which 3/2 kT equals the energy separation between the l = 0 and l = 1 energy levels
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?
In what ways do atoms in a diatomic molecule behave as though they were held together by a spring? In what ways is this a poor description of the interaction between the atoms?
The air you are breathing contains primarily nitrogen (N2) and oxygen (O2). Many of these molecules are in excited rotational energy levels (l = 1, 2, 3, …), but almost all of them are in the vibrational ground level (n = 0). Explain this difference between the rotational and vibrational
Various organic molecules have been discovered in interstellar space. Why were these discoveries made with radio telescopes rather than optical telescopes?
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 you expect the adjacent levels to move
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 in an l = 1 → l = 0 transition. Explain this
The H2+ molecule consists of two hydrogen nuclei and a single electron. What kind of molecular bond do you think holds this molecule together? Explain.
Van der Waals bonds occur in many molecules, but hydrogen bonds occur only with materials that contain hydrogen. Why is this type of bond unique to hydrogen?
How many different possible electron states are there in the n = 100, l = 2 subshell?(a) 2;(b) 100;(c) 10,000;(d) 10.In photosynthesis in plants, light is absorbed in light-harvesting complexes that consist of protein and pigment molecules. The absorbed energy is then transported to a specialized
Assume that the researchers place an atom in a state with n = 100, l = 2. What is the magnitude of the orbital angular momentum L̅(vector) associated with this state?(a) √2 ℏ;(b) √6 ℏ;(c) √1200 ℏ;(d) √110,100 ℏ.In photosynthesis in plants, light is absorbed in
In the Bohr model, what is the principal quantum number n at which the excited electron is at a radius of 1 µm?(a) 140;(b) 400;(c) 20;(d) 81.
Electrons in the lower of two spin states in a magnetic field can absorb a photon of the right frequency and move to the higher state.(a) Find the magneticfield magnitude B required for this transition in a hydrogen atom with n = 1 and l = 0 to be induced by microwaves with wavelength λ.(b)
Can a hydrogen atom emit x rays? If so, how? If not, why not?
An atom in its ground level absorbs a photon with energy equal to the K absorption edge. Does absorbing this photon ionize this atom? Explain.
The nucleus of a gold atom contains 79 protons. How does the energy required to remove a 1s electron completely from a gold atom compare with the energy required to remove the electron from the ground level in a hydrogen atom? In what region of the electromagnetic spectrum would a photon with this
What is the “central-field approximation” and why is it only an approximation?
The ionization energies of the alkali metals (that is, the lowest energy required to remove one outer electron when the atom is in its ground state) are about 4 or 5 eV, while those of the noble gases are in the range from 11 to 25 eV. Why is there a difference?
A small amount of magnetic-field splitting of spectral lines occurs even when the atoms are not in a magnetic field. What causes this?
On the basis of the Pauli exclusion principle, the structure of the periodic table of the elements shows that there must be a fourth quantum number in addition to n, l, and ml . Explain.
Use Table 41.3 to help determine the ground-state electron configuration of the neutral gallium atom (Ga) as well as the ions Ga+ and Ga-. Gallium has an atomic number of 31. Table 41.3 Ground-State Electron Configurations Atomic Electron Configuration Element Symbol Number (Z) Hydmgen Helium H
Why do the transition elements 1Z = 21 to 302 all have similar chemical properties?
The central-field approximation is more accurate for alkali metals than for transition metals such as iron, nickel, or copper. Why?
In the ground state of the helium atom one electron must have “spin down” and the other “spin up.” Why?
In the Stern–Gerlach experiment, why is it essential for the magnetic field to be inhomogeneous (that is, nonuniform)?
What is the energy difference between the two lowest energy levels for a proton in a cubical box with side length 1.00 × 10-14 m, the approximate diameter of a nucleus?
The Stern–Gerlach experiment is always performed with beams of neutral atoms. Wouldn’t it be easier to form beams using ionized atoms? Why won’t this work?
Why is the analysis of the helium atom much more complex than that of the hydrogen atom, either in a Bohr type of model or using the Schrödinger equation?
A photon is emitted when an electron in a three dimensional cubical box of side length 8.00 × 10-11 m makes a transition from the nX = 2, nY = 2, nZ = 1 state to the nX = 1, nY = 1, nZ = 1 state. What is the wavelength of this photon?
Dots that are the same size but made from different materials are compared. In the same transition, a dot of material 1 emits a photon of longer wavelength than the dot of material 2 does. Based on this model, what is a possible explanation?(a) The mass of the confined particle in material 1 is
According to this model, which statement is true about the energy-level spacing of dots of different sizes?(a) Smaller dots have equally spaced levels, but larger dots have energy levels that get farther apart as the energy increases.(b) Larger dots have greater spacing between energy levels than
A harmonic oscillator absorbs a photon of wavelength 6.35 mm when it undergoes a transition from the ground state to the first excited state. What is the groundstate energy, in electron volts, of the oscillator?
Sketch the wave function for the potential-energy well shown in Fig. Q40.26 when E1is less than U0and when E3is greater than U0.Figure Q40.26 UCx) 00 00 Uo х
Compare the allowed energy levels for the hydrogen atom, the particle in a box, and the harmonic oscillator. What are the values of the quantum number n for the ground level and the second excited level of each system?
In Fig. 40.28, how does the probability of finding a particle in the center half of the region -A < x < A compare to the probability of finding the particle in the outer half of the region? Is this consistent with the physical interpretation of the situation? Fig.40.28 The larger the value
The probability distributions for the harmonic-oscillator wave functions (see Figs. 40.27 and 40.28) begin to resemble the classical (Newtonian) probability distribution when the quantum number n becomes large. Would the distributions become the same as in the classical case in the limit of very
The wave function shown in Fig. 40.20 is nonzero for both x < 0 and x > L. Does this mean that the particle splits into two parts when it strikes the barrier, with one part tunneling through the barrier and the other part bouncing off the barrier? Explain.Fig.40.20 The wave function is
Qualitatively, how would you expect the probability for a particle to tunnel through a potential barrier to depend on the height of the barrier? Explain.
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 a particle passes through regions where E is less than U. Is this a contradiction? Explain.
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 iron atoms?Fig.40.17

Showing 200 - 300 of 2042

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Last

Step by Step Answers

Services

Sitemap
Fun
Definitions
Become Tutor
Used Textbooks
Study Help Categories
Recent Questions
Expert Questions
Campus Wear
Sell Your Books

Company Info

Security
Copyrights
Privacy Policy
Terms & Conditions
SolutionInn Fee
Scholarship
Online Quiz
Give Feedback, Get Rewards

Get In Touch

About Us
Contact Us
Career
Jobs
FAQ
Student Discount
Campus Ambassador

Secure Payment

Download Our App

© 2026 SolutionInn. All Rights Reserved