Solve 2d plss

Dear Student

2a)
Ultrasonic waves has shortest wavelength.
As the wavelength of a wave becomes smaller than the obstacle that it encounters, the wave is no longer able to diffract around the obstacle, instead the wave reflects off the obstacle.
2 c
We cannot hear the sound produced due to vibration of second pendulum because the frequency of sound produced by it is 0.5 Hz as it time period is 2s. This is infrasonic sound.
The frequency of vibrations produced by a second pendulum does not fall under human ear's audible range.

2d
$$\begin{gathered} Speed = \frac{Dis\tan ce}{time} \\ Time =\frac{Distance}{Speed} =\frac{2000}{340} =5.88s \\ so B will hear the sound after 5.88 seconds. \end{gathered}$$
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