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. [2012]

Question

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. [2012]

Smart Achievers · Accepted Answer

(2, 4)

When a sound pulse is reflected from the open end of a pipe, its phase changes by 180°. A high-pressure pulse i.e., compression is reflected as a low-pressure pulse i.e., rarefaction.

When a sound pulse is reflected through a rigid boundary (closed end of a pipe), no phase change occurs. Therefore, a high-pressure pulse is reflected as a high-pressure pulse.

Solution

Q.
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. [2012]

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

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

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

4 a high-pressure pulse starts travelling up the pipe, if the other end of the pipe is closed.

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