Question

The concept of secondary wavelets was given by

• A. Fresnel
• B. Maxwell
• C. Huygens
• D. Newton

Hint:

Remember the key contributions of scientists in wave optics: Huygens gave the principle of secondary wavelets, Young demonstrated interference (double-slit experiment), and Fresnel explained diffraction by combining Huygens' principle with interference. Newton is associated with the particle theory of light, which contrasts with the wave theory.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The question asks to identify the scientist who proposed the concept of secondary wavelets. This concept is a fundamental part of the wave theory of light, used to explain phenomena like reflection, refraction, and diffraction.
Step 2: Detailed Explanation:
The concept of secondary wavelets was introduced by the Dutch physicist Christiaan Huygens in 1678.
Huygens' Principle states that:
1. Every point on a primary wavefront acts as a source of new disturbances, called secondary wavelets, which travel out in all directions with the same speed as the original wave.
2. The new wavefront at any later time is the forward envelope (the tangential surface in the forward direction) of these secondary wavelets.
This principle successfully explains the propagation of waves and phenomena like reflection and refraction. While Fresnel later modified and refined Huygens' principle to better explain diffraction (leading to the Huygens-Fresnel principle), the original concept of secondary wavelets is credited to Huygens.
- Fresnel built upon Huygens' work to explain diffraction by incorporating the principle of interference of the secondary wavelets.
- Maxwell developed the electromagnetic theory of light, describing light as electromagnetic waves.
- Newton proposed the corpuscular (particle) theory of light.
Step 3: Final Answer:
The concept of secondary wavelets was given by Huygens. Therefore, option (C) is the correct answer.