Michelson - Morley Experiment

Question 1

Principle of MM interferemoter

Answer 1

Try and measure the speed of light in different directions. According to classical physics, if light is going same direction as earth, speed would be c+v and if opposite c-v.

Question 2

How did they perform the experiment?

Answer 2

Monochromatic light strikes partial reflector and some light is reflected and travels to mirror 2, and some light passes and travels to mirror 1.

Beams are reflected at mirrors 1 and 2. When beams meet back at partial reflector, interference occurs.

They then rotated the apparatus 90 degrees and repeated it. This should cause a change in phase difference as SoL was predicted to be different in both directions.

Question 3

Findings

Answer 3

No shift was detected. Ether theory is incorrect.

Absolute motion seemed to be impossible to detect and SoL appeared to be same in every direction.

Question 4

Invariance of SoL

Answer 4

This was of extreme sig to the development of relativity.

Question 5

What is an Inertial Frame?

Answer 5

Frame where Newtons 1st law is obeyed, moving at constant velocity, or at rest, with no acceleration.