Page 50 - SP015 Past Years PSPM Chapter 6 -14 Ver 2020

PHYSICS PSPM SEM 1 1999 - 2017

Application of Standing Wave ~ Air Column

PSPM JAN 2000/2001 SF035/2 No. 9(c)

39. You are given a closed air column of 80 cm long. When a sound source with a speed of
-1
344 m s is placed near the opened end, stationary wave is generated in the air column.
(a) Draw the stationary wave formed for fundamental tone, first overtone, and second
overtone. [3 m]
(b) Calculate the frequency of fundamental tone and third overtone. [3 m]

PSPM 2002/2003 SF017/2 No. 5

40. Calculate the minimum length of a pipe that has a fundamental frequency of 300 Hz if
the pipe is
(a) closed at one end. [2 m]
(b) opened at both ends. [2 m]
-1
(Speed of sound = 333 m s )

PSPM 2004/2005 SF017/2 No. 5

41. By neglecting the end correction, calculate
(a) the fundamental frequency and the third harmonic frequency for a 0.2 m closed
tube. [2 m]
(b) the second harmonic frequency for a 0.2 m opened tube. [1 m]
-1
(The speed of sound wave in air is 340 m s .)

PSPM 2005/2006 SF017/2 No. 12(b)

42. opened end closed end

S P

x = 0 2 m
m
FIGURE 10.5
FIGURE 10.5 shows a loud speaker S emitting sound wave of frequency 205 Hz in
front of a closed pipe P. The length of the pipe is 2 m and its opened end is at position
x = 0 m. The air column resonates at fifth harmonics.
(a) Draw the stationary wave pattern formed in the air column at its fifth harmonics.
Label all the nodes and antinodes at their respective positions. [3 m]
(b) The maximum amplitude of the stationary wave formed in the pipe is 0.02 m.
Calculate the amplitude for a particle at x = 0.3 m. Neglect end correction factor.
[5 m]
(c) Write an expression in terms of time t for the displacement of the particle in the
stationary wave. [5 m]

50