Modern Physics

Citation

Krane, K. S. (2019). Modern Physics (4th ed.). Wiley.

Chapter Summary

The book has 15 chapters in about 590 pages, followed by five appendices (constants and conversion factors, complex numbers, the periodic table, a table of atomic masses, and a list of milestones in the history of modern physics), answers to odd-numbered problems and two indexes. Every chapter ends with Questions and Problems. The publisher says each major concept is presented first from a historical perspective and then through a modern lens with experimental evidence, so that the chapters form a continuous "storyline".

Chapter 1: Some Deficiencies of Classical Physics

Reviews classical physics (the sample chapter treats momentum and energy in collisions, electromagnetism, and thermodynamics and kinetic theory) and then sets out where it fails: classical concepts of space and time, and classical particle statistics, with a closing section on the relation of theory, experiment and law. The chapter includes worked examples and a chapter summary.

Chapter 2: The Special Theory of Relativity

From classical relativity and the Michelson–Morley experiment to Einstein's postulates, their consequences, the Lorentz transformation, the twin paradox, relativistic dynamics, conservation laws in relativistic decays and collisions, and experimental tests.

Chapters 3–4: The Particle-Like Properties of Electromagnetic Radiation; The Wavelike Properties of Particles

Chapter 3 covers the photoelectric effect, thermal radiation, the Compton effect and other photon processes, ending with the question of particles or waves. Chapter 4 turns the question around with de Broglie's hypothesis and its experimental evidence, the uncertainty relationships, wave packets, and probability and randomness.

Chapter 5: The Schrödinger Equation

Behaviour of a wave at a boundary, confining a particle, the equation itself and its applications, the simple harmonic oscillator, and steps and barriers.

Chapters 6–8: The Rutherford–Bohr Model of the Atom; The Hydrogen Atom in Wave Mechanics; Many-Electron Atoms

Chapter 6 follows scattering experiments, the Rutherford nuclear atom, line spectra and the Bohr model, including its deficiencies. Chapter 7 begins with a one-dimensional atom and proceeds to angular momentum, hydrogen wave functions, probability densities, intrinsic spin, the Zeeman effect and fine structure. Chapter 8 covers the Pauli exclusion principle, electronic states, screening, the properties of the elements, X rays, addition of angular momenta and lasers.

Chapters 9–11: Molecular Structure; Statistical Physics; Solid-State Physics

Chapter 9 covers the hydrogen molecule, covalent and ionic bonding, and molecular vibrations, rotations and spectra. Chapter 10 develops statistical analysis, classical and quantum statistics, the density of states, the Maxwell–Boltzmann distribution, and applications of Bose–Einstein and Fermi–Dirac statistics. Chapter 11 covers crystal structures, heat capacity, electrons in metals, band theory, superconductivity, semiconductors and devices, and magnetic materials.

Chapters 12–13: Nuclear Structure and Radioactivity; Nuclear Reactions and Applications

Nuclear constituents, sizes, masses and binding energies, the nuclear force, quantum states in nuclei and radioactive decay (alpha, beta, gamma, natural radioactivity); then nuclear reactions, fission, fusion, nucleosynthesis and applications.

Chapters 14–15: Elementary Particles; Cosmology: The Origin and Fate of the Universe

Chapter 14 covers the four basic forces, particle classification, conservation laws, interactions and decays, the quark structure of mesons and baryons and the Standard Model. Chapter 15 covers the expansion of the Universe, the cosmic microwave background, dark matter, general relativity and its tests, stellar evolution and black holes, big-bang cosmology, the formation of nuclei and atoms, and experimental cosmology.

Key Concepts

Chapters 1–5: Classical Limits, Relativity, Quantum Basics

• Lorentz transformation: the relation between the coordinates of events in different inertial frames.
• Wave-particle duality: radiation behaving as particles and particles behaving as waves.
• Uncertainty relationships: the limits on simultaneous knowledge of conjugate quantities.
• Schrödinger equation: the wave equation that governs a particle's quantum state.

Chapters 6–11: Atoms, Molecules, Statistics, Solids

• Bohr model and its deficiencies: the first quantized atom, and why wave mechanics replaced it.
• Pauli exclusion principle: the rule that shapes many-electron atoms and the periodic table.
• Quantum statistics: the Bose–Einstein and Fermi–Dirac distributions and their applications.
• Band theory: the account of metals, insulators and semiconductors.

Chapters 12–15: Nuclei, Particles, Cosmology

• Binding energy: the energy that holds a nucleus together.
• Standard Model: the quark and lepton picture of particles and their interactions.
• Big-bang cosmology: the expansion, microwave background and nucleosynthesis account of the Universe.

Critical Analysis

Strengths

• Historical and experimental motivation. The publisher highlights concepts developed first historically and then through experimental results, and the sample chapter opens with the experiments and failures that prompted modern physics. Appendix E collects milestones in the history of the field.
• Wide coverage in a single course text. The 15 chapters run from relativity and quantum theory through atoms, molecules, statistical physics, solids, nuclei and particles to cosmology, so one book can serve a full year or be cut to a term.
• Fourth-edition updates. The publisher lists new experimental results on gravitational waves, relativity and the Higgs boson, and updated coverage of neutrino mass, microwave-background studies, dark matter and dark energy, plus new and revised examples, exercises and end-of-chapter problems.
• Practice material. Each chapter closes with Questions and Problems, the sample chapter contains worked examples, and answers to the odd-numbered problems are printed at the back.

Limitations

• Breadth over depth. With 15 topics in about 590 pages, the Schrödinger equation receives a single chapter before atoms arrive in Chapter 7, and general relativity gets a seven-page section (15.4) and four pages on its tests (15.5) within the last chapter. Students heading into specialist courses will need fuller treatments.
• Little mathematical support. The only mathematical appendix is on complex numbers, so other tools must come from prerequisite courses or be introduced within chapters.

Where It Fits in the Course

Krane is one of two full-length modern physics texts at the sophomore level in this course list. Thornton, Rex and Hood's Modern Physics for Scientists and Engineers covers similar ground in 16 chapters, with separate chapters on semiconductor theory and devices, on particle physics, and on astrophysics and general relativity, while Krane compresses solids and semiconductors into one chapter and nuclear physics into two.

OpenStax's University Physics Volume 3 is a free, calculus-based introduction to relativity and quantum ideas that suits students who want a lighter first pass. Taylor and Wheeler's Spacetime Physics develops special relativity through the spacetime interval and gives a much fuller account than Krane's single chapter; Schutz's A First Course in General Relativity and Carroll's Spacetime and Geometry are the undergraduate and graduate steps for general relativity that Krane only outlines.

How to Use This Book

The publisher describes the book as appropriate for second-year science and engineering undergraduates. It opens with a review of classical physics (Section 1.1) and has an appendix on complex numbers, so a calculus-based introductory physics course is the natural preparation.

A two-semester course can follow the book in order. For one semester, cover Chapters 1–8 (relativity, wave-particle duality, the Schrödinger equation and atoms), then choose among Chapters 9–11 (molecules, statistical physics, solids) and 12–15 (nuclei, particles, cosmology) according to the department's emphasis. Chapter 1 can be read quickly as a review. Use the Questions to test conceptual understanding before the Problems, and check answers to odd-numbered problems at the back of the book.