Question

In interference and diffraction, the light energy is redistributed. If it reduces in one region, producing a dark fringe, it increases in another region, producing a bright fringe.
A. As there is no gain or loss of energy, these phenomena are consistent with the principle of conservation of energy.
B. Diffraction and interference are characteristics exhibited only by light waves.
Choose the correct answer from the options given below:

• A. A is false, but B is true
• B. A is true and B is also true
• C. A is true, but B is false
• D. Both A and B are false

Hint:

Remember that "Interference" is the fundamental test for wave nature. If something (like an electron or a sound pulse) can interfere, it is behaving as a wave.

Answer 1

The Correct Option is C

Step 1: Understanding the Topic:
This conceptual question belongs to "Wave Optics." It tests the fundamental nature of waves and the laws they obey. Specifically, it addresses the conservation of energy during superposition and the universality of wave behaviors across different types of waves.
Step 2: Key Formulas and Approach:
There are no numerical formulas here, but the core principles are:
Law of Conservation of Energy: Energy cannot be created or destroyed.
Definition of a wave: A disturbance that transfers energy.

Step 3: Detailed Explanation:

Statement A analysis: In interference, when two waves overlap, the resulting intensity is not just the sum of individual intensities at every point ($I \neq I_1 + I_2$). However, the {average} intensity across the whole screen is exactly $I_1 + I_2$. The energy that "disappears" from the dark fringes is exactly the same amount of energy that "appears" as extra brightness in the bright fringes. Thus, energy is conserved. (True)
Statement B analysis: Interference and diffraction are properties of {all} waves. This includes sound waves (which you can hear interfering), water waves, radio waves, and even matter waves like electrons. Light is just one example of a wave that shows these properties. Saying "only light" exhibits them is scientifically incorrect. (False)
Conclusion: Since A is correct and B is incorrect, the answer is (C).
Step 4: Final Answer:
Statement A is true, but Statement B is false.