In a literal sense, the term modern physics means up-to-date physics. Modern physics refers to post-1900 physics which incorporates elements of quantum mechanics and relativity. Modern physics is often encountered when dealing with extreme conditions. Modern physics mainly consists of concepts like Photoelectric Effect, Bohr's Theory, X-Rays, de Broglie wavelength of matter waves, Moseley's Law, Radioactivity and Nuclear physics. Among all these topics, Nuclear physics and Radioactivity are most important.
-