3 e m u o l V Mir Publishers Moscow ELEMENTARY TEXTBOOK ON PHYSICS Edited by G.S. Landsberg These three volumes form a course on elementary physics that has become very popular in the Soviet Union. Each sectioh was written by an authority in theappropriate field, while the overall unity and editing was supervised by Academician G.S. Landsberg (1890-1957). This textbook has gone through ten Russian editions and a great deal of effort went into the last edition to introduce SI units and change the terminology and notation for the physical units. A feature of this course is the relatively small number of formulas and mathematical manipulations. Instead, attention was focussed on explaining physical phenomena in such a way as to combine scientific rigour and a form understandable to school children.Another aspect of the text is the technological application of the physical laws. These features make the text a world-class textbook. For students preparing to enter universities andcolleges to study physics, and for those it high schools specialising in physics. ELEMENTARY TEXTBOOK ON PHYSICS Volume 3 3 /lEM EHTAPHbm YHEEHMK 0 3 M MKM nofl peflaKL^neki axafleMMKa r.C. JIAHACBEPrA B 3-X TO Max TOM 3 KOflEBAHMfl M BOnHbl. OnTMKA. ATOMHAfl M flflEPHAfl OM3MKA H3flaienbCTBO «HayKa» MocKBa ELEMENTARY TEXTBOOK ON PHYSICS Edited by G.S. Landsberg In three volumes Volume 3 OSCILLATIONS AND WAVES OPTICS ATOMIC AND NUCLEAR PHYSICS Mir Publishers Moscow ^ Translated from Russian by Natalia Wadhwa First published 1989 Revised from the 1986 Russian edition Ha QH2AUUCKOM X3blKe Printed in the Union of Soviet Socialist Republics © lfoaaTejibCTBO «Hayxa». niaBHaa penaKima ISBN 5-03-000264-2 <t>H3HKo-MaTeMaTHqecKoft jmTepaTypbi, 1986 ISBN 5-03-000223-5 © English translation, Mir Publishers, 1989 Contents Preface to the First Russian Edition 11 Part One. Oscillations and Waves 13 Chapter 1. Basic Concepts. Mechanical Vibrations 13 1.1. Periodic Motion. Period (13). 1.2. Oscillatory Systems. Free Oscillations (13). 1.3. Pendu­ lum: Kinematics of Oscillations (15). 1.4. Vibrations of a Timing Fork (16). 1.5. Harmonic Oscil­ lations. Frequency (18). 1.6. Phase Shift (21). 1.7. Dynamics of Pendulum Oscillations (23). 1.8. Formula for the Period of a Simple Pendulum (25). 1.9. Elastic Vibrations (27). 1.10. Torsional Vibrations (29). 1.11. Effect of Friction. Damping (30). 1.12. Forced Vibrations (33). 1.13. Resonance (34). 1.14. Effect of Friction on Resonance Phenomena (36). 1.15. Examples of Resonance Phenomena (37). 1.16. Resonance Phenomena Induced by an Anharmonic Periodic Force (39). 1.17. The Relation Between the Form and Harmonic Composition of Periodic Oscil­ lations (42). Chapter 2. Acoustic Vibrations 30 2.1. Acoustic Vibrations (30). 2.2. Subject of Acoustics (47). 2.3. Musical Tone. Laudness and Pitch (48). 2.4. Tfcmbre (49). 2.5. Acoustic Resonance (51). 2.6. Recording and Reproduction of Sounds (53). 2.7. Analysis and Synthesis of Sound (54). 2.8. Noises (55). Chapter 3. Electric Oscillations 58 3.1. Electric Oscillations and Methods of Their Observation (58). 3.2. Oscillatory Circuit (61). 3.3 Mechanical Analogy. Thomson Formula (64). 3.4. Electric Resonance (67). 3.5. Undamped Oscillations. Self-Excited Oscillatory Systems (70). 3.6. Valve Oscillator (73). 3.7. Theory of Os­ cillations (75). Chapter 4. Wave Phenomena 79 4.1. Waves (79). 4.2. Wave Propagation Velocity (81). 4.3. Radiolocation, Hydroacoustic Detec­ tion and Sound Ranging (83). 4.4. Thinsverse Waves in a Cord (85). 4.5. Longitudinal Waves