Final answer:
The frequency of a monotonous sound is constant and does not change with intensity, amplitude, or distance from the source. Amplitude and frequency of a wave are independent of each other, and the energy of a wave increases with its amplitude, not frequency. Amplitude of a sound wave decreases with distance due to the spreading of the wave's energy.
Step-by-step explanation:
When discussing the frequency of a monotonous sound, it is important to understand that the frequency is the number of cycles (or wavelengths) that pass a given point in a second. It is a measure of how often the particles of a medium vibrate when a wave passes through the medium. Therefore, the correct statement regarding the frequency of a monotonous sound is b) It is constant. Frequency is determined by the source of the sound and does not change with intensity, amplitude, or distance from the source, provided the sound is monotonous.
For the question related to the relationship between amplitude and frequency of a wave, the correct option is a) The amplitude and the frequency of a wave are independent of each other. Amplitude represents the height of the wave and is related to the energy of the wave, not its frequency. While the energy of a wave increases with an increase in amplitude, this does not affect the frequency. Additionally, when the period of a wave (the time for one complete cycle) increases, the frequency (the number of cycles per second) conversely decreases.
As for the amplitude of a sound wave decreasing with distance from its source, this occurs because the energy of the wave is spread over an increasingly larger area, not because the speed or wavelength of the sound wave changes.