Answer:
The correct answer to the question is
448 m/s
Explanation:
The fundamental frequency is the lowest resonant frequency of a vibration. The nature of a standing wave in a tube with one end closed which is at the the fundamental frequency is to have the node of the wave at the closed end and the wave anti-node at the opened end making a quarter of the wavelength.
Therefore the length of the gas column, 1.40 m = λ/4
So that λ = 4 × 1.4 = 5.6 m
Therefore from v = fλ
Where
f = frequency = 80.o Hz
v = wave speed
we have the wave speed v = 5.6×80 = 448 m/s
