Answer:
344Hz
Step-by-step explanation:
First we need to more that the frequency will inky resonate in the portion not containing water. If the total length is 1m and the filled with water up to 75cm, the length of the air column will be 100cm - 75cm = 25cm
Fundamental frequency of a closed pipe fo = V/4L
V is the velocity of sound in air
L is the length of the air column
Given V = 344m/s
L = 25cm = 0.25m
fundamental resonant frequency = 344/4(0.25)
= 344/1
= 344Hz