What does the Y-axis of a spectrogram represent?

The Y-axis of a spectrogram represents frequency. In a spectrogram, different frequencies of sound are displayed vertically. The positioning on this axis indicates how high or low the frequencies are, which is crucial for analyzing the characteristics of speech and other sounds. Each point along the Y-axis corresponds to a specific frequency, allowing for the visualization of how different frequencies contribute to the overall sound over time.

In this context, while intensity relates to the amplitude of sound and would be represented through color or brightness on the spectrogram, it does not appear on the Y-axis. Time, which is represented on the X-axis, shows how sound changes and evolves. Pitch, which is perceptually linked to frequency, does not directly align with the specific representation of frequency on the spectrogram's Y-axis. Thus, the correct answer is indeed the representation of frequency, which is crucial for understanding sound analysis.