A glass tube of `1.0 m` length is filled with water . The water can be drained out slowly at the bottom of the tube . If a vibrating tuning fork of frequency `500 c//s` is brought at the upper end of the tube and the velocity of sound is `330 m//s`, then the total number of resonances obtained will be

Options

A. 4
B. 3
C. 2
D. 1

Answer

B

Explanation

Wavelength,
`lamda=("Velocity")/("Frequency")=(330ms^(-1))/(500ms^(-1))=0.66m`
The resonance occurs at
`lamda/4,(3lamda)/4,(5lamda)/4,(7lamda)/4,…..
i.e., at 0.165 m, 0.495 m, 0.825 m, 1.155 m. As the length of the tube is only 1.0 m, hence 3 resonances will be observed.