Question

Assertion: In a sound wave, a displacement node is | a pressure antinode and vice versa
Reason: Displacement node is a point of minimum displacement

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (B)

At the point where a compression and a rarefaction meet, the displacement is minimum and it is called displacement node. At this point, the pressure difference is maximum, that is at same time, it is a pressure antinode. On the other hand, at the mid-point of a compression or a rarefaction, the displacement variation is maximum. Such a point is displacement antinode. However such a point is pressure node, as pressure variation is minimum at such a point