Notes of Chapter 17: Advent of Modern Physics of “Physics XII” for FSc Part 2 published by Sindh Textbook Board, Jamshoro. These notes are very helpful to prepare Physics paper of FSc Part 2 for Sindh Board. These can also be consider as refrence notes for Federal Board, Multan Board, Faisalabad Board, Sargodha Board, Gujranwala Board, DG Khan Board, Rawalpindi Board or any other board of Pakistan.

The term modern physics refers to the post-Newtonian conception of physics. The term implies that classical descriptions of phenomena are lacking, and that an accurate, “modern”, description of reality requires theories to incorporate elements of quantum mechanics or Einsteinian relativity, or both …