Question

The phenomenon of interference is shown by:

• A. longitudinal mechanical wave only
• B. transverse mechanical wave only
• C. electromagnetic waves only
• D. all these waves

Hint:

Interference follows from the superposition principle, so sound, string waves and light all show it.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Interference is the redistribution of energy when two or more waves overlap. It follows from the superposition principle, which holds for any wave that obeys a linear wave equation.

Step 2: Condition for Interference:
Two sources must be coherent. The waves must also be able to add at a point, which is true for longitudinal waves (such as sound), transverse mechanical waves (such as waves on a string) and electromagnetic waves (such as light).

Step 3: Examples:
Two loudspeakers fed by the same signal give loud and soft regions: longitudinal wave interference. Two pulses on a string add and cancel: transverse mechanical wave interference. Young's double slit shows bright and dark fringes: electromagnetic wave interference.

Step 4: Why the Other Options Are Wrong:
Options (A), (B) and (C) each say 'only', which excludes the other kinds of waves. All of these waves show interference, so these statements are false.

Final Answer:
Interference is shown by all these waves. This is option (D). \[ \boxed{\text{All these waves}} \]