Question

The failure of Michelson-Morley experiment indicated:

• A. Existence of ether medium
• B. Speed of light is directional
• C. Speed of light is invariant
• D. Light has dual nature

Hint:

Think of the null result of the Michelson-Morley experiment as a major turning point for modern physics. Because the result was not what they expected, it paved the way for the special theory of relativity, highlighting the importance of questioning existing dogma in scientific research.

Answer 1

The Correct Option is C

The Michelson-Morley experiment was designed to detect the presence of a hypothetical medium called “ether” through which it was believed that light propagated. The experiment, conducted using an interferometer, aimed to measure the variation in the speed of light due to the Earth’s motion through the ether. The expectation was that the speed of light would be different depending on the direction relative to Earth’s movement, i.e., have different values when measured along and perpendicular to Earth’s velocity.
However, the experiment produced a null result. This means that no variation in the speed of light could be measured regardless of the orientation of the equipment with respect to the earth’s orbit around the sun. This result was inconsistent with the expectation that an ether medium existed and that the speed of light depends on the motion of the light source. It led to the conclusion that the speed of light is constant for all observers, regardless of their motion or that of the light source. This key finding was later incorporated into Einstein’s theory of special relativity, which states that the speed of light in a vacuum (c) is a universal constant. The Michelson-Morley experiment therefore did not prove any of the other options mentioned, and was instead very important in the establishment of the Special Theory of Relativity.