Final answer:
The units of pulse repetition frequency (PRF) are 1/seconds or hertz (Hz), symbolically indicated as 'per second' which means the number of pulses occurring per second.
Step-by-step explanation:
The units of pulse repetition frequency (PRF) are in 1/seconds, which is read as "per second". The concept of PRF is related to how often a pulsed wave occurs in one second. As we note that units of time (seconds) are in the denominator and indicated by a −1 power, the correct option for the units of PRF is B. 1/seconds.
PRF is a common term in fields such as radar and ultrasound technology, where pulses of waves are used in rapid succession. It is important to recognize that the unit for frequency is hertz (Hz), and since PRF is effectively a frequency, the units can also be expressed as Hz, where 1 Hz = 1 cycle/second.