Final answer:
The duty factor is the ratio of the pulse duration to the pulse repetition interval, giving a value of 0.001 in this case, which corresponds to option A.
Step-by-step explanation:
The duty factor, also known as the duty cycle, is calculated by dividing the pulse duration by the pulse repetition interval (PRI). In the given case, the pulse duration is 1 microsecond (µ1μs), and the pulse repetition interval is 1 millisecond (µ1ms). To find the duty cycle, use the equation:
Duty Factor (D) = Pulse Duration (T) / Pulse Repetition Interval (PRI).
Substitute the values:
D = 1μs / 1ms = 1μs / 1000μs = 0.001.
Therefore, the duty factor is 0.001, which corresponds to option A.