IDNLearn.com is designed to help you find reliable answers quickly and easily. Whether your question is simple or complex, our community is here to provide detailed and trustworthy answers quickly and effectively.
1 whole wave is 1 crest and 1 trough.
20 crests and 20 troughs is 20 whole waves.
20 waves / 0.4 seconds = 50 waves per second.
Frequency = 50 Hz