The two major physical theories of the 20th century are
A) electromagnetic theory and the theory of gravity.
B) superconductivity and the theory of light.
C) electromagnetic theory and quantum theory.
D) quantum theory and the theory of relativity.
E) the theory of relativity and electromagnetic theory.

Question

Quizplus · Accepted Answer

The two major physical theories of the 20th century are quantum theory, which deals with the behavior of particles at the smallest scales, and the theory of relativity, which addresses the structure of space-time and gravity.

The Two Major Physical Theories of the 20th Century Are