Regarding an open organ pipe , which of the following is correct?

Vibrations in open organ pipe

The frequency of open organ pipe is

Compare the length of a closed organ pipe and an open organ pipe, if the second overtone of the open pipe is unison with the second overtone of the closed organ pipe.

Compare the length of a closed organ pipe and an open organ pipe, if the second overtone of the open pipe is unison with the second overtone of the closed organ pipe.

The fundamental frequency of a closed organ pipe is equal to the first overtone of an open organ pipe. If the length of the open pipe is 60 cm, What is the length of the closed pipe?

Third overtone of a closed organ pipe is in unison with fourth harmonic of an open organ pipe. Find the ratio of the lengths of the pipes.

Third overtone of a closed organ pipe is in unison with fourth harmonic of an open organ pipe . Find the ratio of the lengths of the pipes.