دانلود کتاب Introduction to modern physics

'The purpose of this book is, frankly, pedagogical. The author has attempted to present such a discussion of the origin, development, and present status of some of the more important concepts of physics, classical as well as modem, as will give to the student a correct perspective of the growth and present trend of physics as a whole. Such a perspective is a necessary basis—so the author, at least, believes—for a more intensive study of any of the various subdivisions of the subject. While for the student whose interests are cultural, or who is to enter any of the professions directly or indirectly related to physics, such as engineering, chemistry, astronomy, or mathematics, an account of modern physics which gives the origin of current theories is likely to be quite as interesting and valuable as in a categorical statement of the theories themselves. Indeed, in all branches of human knowledge the ‘why’ is an absolutely indispensable accompaniment to the ‘what.’ ‘Why?’ is the proverbial question of childhood. ‘Why?* inquires the thoughtful (!) student in classroom or lecture hall. *Why?’ demands the venerable scientist when listening to an exposition of views held by a colleague. Accordingly, if this book seems to lay somewhat greater emphasis on matters which are frequently regarded as historical, or, if here and there a classical experiment is described in greater detail than is customary, it is with a desire to recognize the importance of ‘why.’