Amplitude is defined as which of the following?

• A. The speed of the signal
• B. The size or signal strength of a waveform
• C. The time delay between two signals
• D. The direction of propagation

Answer: (B)

Amplitude describes the size or strength of a waveform—the height of the wave from its baseline. It tells you how large the signal is at any moment, and in practical terms often relates to power, since power is roughly proportional to the square of the amplitude. For a sine wave, amplitude is the peak value (the maximum excursion from zero), and the RMS value is another way to express the effective power of that signal. The other properties describe different aspects: speed is how fast the wave travels through a medium, the time delay between signals is about timing or phase offset, and the direction of propagation is the path the wave takes. So amplitude is best defined as the size or signal strength.