In the context of electrical systems, how is amplitude measured?

In electrical systems, amplitude refers to the maximum value of a waveform, which is typically measured in volts. Therefore, the unit that correctly represents amplitude is volts, denoted by "V." This measurement indicates the peak voltage level of an electrical signal.

The other units mentioned in the choices have specific applications in electrical contexts but do not directly measure amplitude. Hertz (Hz) measures the frequency of oscillations or cycles per second, milliamperes (mA) generally quantify the flow of current, and microseconds (us) refer to a time interval. Hence, volts are the correct unit for measuring the amplitude of an electrical signal.