Comparison with modern physics In contrast to classical physics, "modern physics" is a slightly looser term that may refer to just quantum physics or to 20th- and 21st-century physics in general. Modern physics includes quantum theory and relativity, when applicable.
Comparison with mo,dern physics In contrast to classical physics "mo.dern physics" is a slightly looser term that may refer to just quantum physics or to 20th- and 21st-century physics in general. Modern physics includes quantum theory and relativity, when applicable