Explanation:

Shrillness is a characteristic of sound that is determined by its frequency. Let's understand what frequency is and how it affects the sound's shrillness.

Frequency:

Frequency is the number of complete cycles or vibrations that a sound wave completes in one second. It is measured in Hertz (Hz). The higher the frequency, the more cycles or vibrations a sound wave completes in one second.

Shrillness:

Shrillness is the quality of a sound that is sharp, high-pitched, and piercing. It is a subjective perception of sound, but it can be objectively measured.

Relation between Frequency and Shrillness:

The frequency of a sound wave determines its pitch and, to some extent, its shrillness. The higher the frequency, the higher the pitch and the more shrill the sound. For example, the sound of a whistle is shrill because it has a high frequency.

Amplitude and Shrillness:

Amplitude is the magnitude of the sound wave and determines its loudness. However, it does not affect the sound's shrillness. A sound can be loud and not shrill, or it can be soft and shrill.

Conclusion:

In conclusion, the shrillness of the sound is determined by the frequency of vibration. The higher the frequency, the more shrill the sound. Amplitude, on the other hand, determines the loudness of the sound but does not affect its shrillness.