In this post, we will look at the book Units of Physical Quantities and their Dimensions by L. A. Sena.The present book sets out in detail the prin­ciples of constructing systems of units, and also the fundamentals of the theory of dimensions. Together with detailed information on the SI system, which is the preferable one at present, a description is given of other systems of units, and also of some non-system units having prac­tical significance.The book is intended for students of technical colleges and will also be helpful for physics in­structors in higher and secondary schools.The book was translated from the Russian by G. Leib and was first published by Mir in 1972. Many thanks to Hitesh for this book.  CONTENTSForeword  7Chapter One. General Concepts on Systems of Basic and Derived Units 111.1. Physical Quantities and Their Units  11 1.2. Direct and Indirect Measurements 16 1.3. Basic and Derived Units  18 1.4. Constructing a System of Units  24 1.5. Selection of Basic Units  34 1.6. Non-System Units  40Chapter Two. Conversion of Units and Dimension Formulas 422.1. Dimension Formulas 422.2. Conversion of Dimension When Using Different Basic Units 472.3. Conversion of Dimensions with Different Defining Relationships 482.4. Determining the Relationship between Units of Different Systems 522.5. Compilation of Conversion Tables 582.6. On the So-called Meaning of Dimension Formulas 592.7. Brief Conclusions on Chapters One and Two 62Chapter Three. Analysis of Dimensions 653.1. Determining Functional Relationships by Comparing Dimensions 65 3.2. The II-Theorem and the Method of Similarity 72Chapter Four. Units of Geometrical and Mechanical Quantities 794.1. Introduction 79 4.2. Geometrical Units 80 4.3. Kinematic Units 91 4.4. Static and Dynamic Units 96 4.5. Units of Mechanical and Molecular Properties of a Substance  109 Chapter Five. Thermal Units 1215.1. Temperature 121 5.2. Temperature Scales 128 5.3. Fixed Temperature Points 130 5.4. Other Thermal Units 130 5.5. Units of Thermal Properties of Substances 135Chapter Six. Acoustic Units 1426.1. Objective Characteristics of Mechanical Wave Pro­cesses 142 6.2. Subjective Characteristics of Sound 1476.3. Some Quantities Connected with the Acoustics of Buildings 150Chapter Seven. Electrical and Magnetic Units 1537.1. Introduction 1537.2. Possible Ways of Constructing Systems of Electrical and Magnetic Units 1547.3. Units of theCGS System 1697.4. Units of the SI System 1827.5. On the So-called Wave Resistance of a Vacuum 1967.6. International Units 198Chapter Eight. Units of Radiation 2018.1. Scale of Electromagnetic Waves  2018.2. Characteristics of Radiant Energy 2028.3. Illumination Engineering Units 207 8.4. Relationship between Subjective and Objective Cha­racteristics of Light 212 8.5. Units of Parameters of Optical Instruments 214 8.6. Units of Optical Properties of a Substance 217Chapter Nine. Selected Units of Atomic Physics 2189.1. Introduction 2189.2. Basic Properties of Atomic and Elementary Particles 2189.3. Effective Interaction Cross Sections 2239.4. Units of Energy in Atomic Physics 2259.5. Ionizing Radiation Units 2299.6. Units of Radioactivity 2319.7. Ionization, Recombination and Mobility Coefficients 2339.8. Natural Systems of Units 235Appendix 1. Logarithmic Units 238Appendix 2. Measuring the Density of a Liquid with an Areo­ meter 241Appendix 3. pH Index 242Appendix 4. Constants 243Appendix 5. Tables 245Bibliography 286Index 288