Question

1. a) Explain Einstein’s theories of special relativity and general relativity.

b) Include at least one piece of evidence in support of each theory.

Answer 1

Relativity is the study of how different observers measure the same event relative to each other.

Special theory of relativity deals with object moving at constant velocity and explains the limit on an object's speed. Two postulate given by Einstein -

1) The laws of physics are the same and can be stated in their simplest form in all inertial frames of reference.

2) The speed of light in vacuum is a constant, independent of the source.

Michelson-Morley experiment demonstrated that the speed of light in vacuum is independent of the motion of the Earth about the Sun which is explained by 2nd postulate.

General Relativity deals with objects undergoing accelerated motion. It is geometric theory of gravitation. According to it, Gravity is the geometric property of space and time or Spacetime. The curvature of Spacetime is directly related to the energy and momentum of matter and radiation present.

The orbit of Mercury is shifting gradually over time due to curvature of Spacetime around massive Sun.