Final answer:
Three-phase full-wave rectification results in a high-frequency ripple due to the use of six diodes that convert the AC input to a higher frequency DC output.
Step-by-step explanation:
When full-wave rectification is applied to three-phase current, a high-frequency ripple is produced. In a three-phase full-wave rectification, six diodes are used, with two for each phase. As a result, the output frequency is higher compared to single-phase rectification. Specifically, if the input is 50 Hz as commonly found in mains electricity, the rectified output frequency will be 300 Hz, which is six times the input frequency because each phase contributes to two pulses per cycle.