Discussion Forum



1)

 A person blows into the open-end of a long pipe. As a result, a high-pressure pulse of air travels down the pipe. When this pulse reaches the other end of the pipe. 


A) a high-pressure pulse starts travelling up the pipe , if the other end of the pipe is open

B) a low-pressure pulse starts travelling up the pipe , if the other end of the pipe is open

C) a low-pressure pulse starts travelling up the pipe, if the other end of the pipe is closed

D) a high pressure pulse starts travelling up the pipe , if the other end of the pipe is closed

Answer:

Option (B,D)

Explanation:

At the open-end phase of pressure wave changes by $180^{0}$. So, compression returns as rarefaction. At closed-end, there is no phase change. So, compression returns as compression and rarefaction as rarefaction.