3.12.3 Special Relativity

Question 1

Describe the Michelson-Morley interferometer setup.

Answer 1

Monochromatic light sent through a semi-silvered mirror at 45 degrees, splitting the light into 2 beams, both sent to their own mirror to be reflected back to the semi-silvered mirror, to both be sent to a detector to show an interference pattern of fringes

Question 2

What is the ‘ether’?

Answer 2

A medium in space proposed to carry light waves

Question 3

What was the point of the Michelson-Morley experiment?

Answer 3

To test the existence of an ‘ether’, by testing the speed of light waves travelling in different directions with the same distance to see if there was a motion changing the speed of one of the light waves

Question 4

What was concluded from the Michelson-Morley experiment, and what is the significance of this result?

Answer 4

After moving the setup 90 degrees to see if the interference pattern changed due to a relative motion caused by an ‘ether’, the interference pattern did not change, so the ether was proved to not exist, and therefore the speed of light is the same in all directions.

Question 5

What is the role of the compensator in the Michelson-Morley experiment?

Answer 5

It makes up for the extra distance travelled by the beam of light reflected by 90 degrees at the semi-silvered mirror