Who proposed that ‘Light is made up of waves propagating perpendicular to the direction of its movement’?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. Huygens.
The concept that "light is made up of waves propagating perpendicular to the direction of its movement" was proposed by the Dutch scientist Christiaan Huygens in the 17th century. Huygens' wave theory of light, presented in his work Traité de la lumière (1690), suggested that light behaves as a wave, and this wave propagates through a medium, which he called the "ether."
According to Huygens, each point on a wavefront could be considered a source of secondary spherical wavelets, which combine to form the next wavefront. This principle, now known as Huygens' Principle, explained many optical phenomena, such as reflection, refraction, and diffraction.
Huygens' wave theory was a significant departure from the earlier particle theory of light and was an important foundation in the understanding of light, even though it was later challenged by Isaac Newton's particle theory and ultimately replaced by the electromagnetic wave theory of light.