First (Fundamental); No
Length of the pipe, l = 20 cm = 0.2 m
Source frequency = nth normal mode of frequency, νn = 430 Hz
Speed of sound, v = 340 m/s
In a closed pipe, the n th normal mode of frequency is given by the relation:
Hence, the first mode of vibration frequency is resonantly excited by the given source.
In a pipe open at both ends, the nth mode of vibration frequency is given by the relation:
Since the number of the mode of vibration (n) has to be an integer, the given source does not produce a resonant vibration in an open pipe.