Question

Assertion (A) It is possible to have interference between the waves produced by two guitars.

Reason (R) For interference of two waves the phase difference between the waves must remains constant.

• A. Both A and R are true and R is the correct explanation of A
• B. Both A and R are true but R is not the correct explanation of A
• C. A is true but R is false
• D. A is false but R is true

Answer 1

Answer: (D)

A is false but R is true.

Answer 2

Explanation:

• Assertion (A): For two waves to produce a sustained interference pattern, they must be coherent. Coherent sources maintain a constant phase difference between them. Waves produced by two independent sources, such as two separate guitars, are generally incoherent. The vibrations of the strings in two different guitars are independent and random with respect to each other, meaning the phase difference between the sound waves they produce will vary randomly and rapidly. Therefore, a stable interference pattern cannot be observed. Hence, Assertion (A) is false.

• Reason (R): This statement correctly defines the condition for observing sustained interference. For interference fringes (regions of constructive and destructive interference) to be stable and observable, the phase difference between the interfering waves must remain constant over time. If the phase difference varies randomly, the interference pattern will shift rapidly, and the average intensity at any point will be uniform, making the interference unobservable. Hence, Reason (R) is true.

Since Assertion (A) is false and Reason (R) is true, the correct choice is that A is false but R is true.