Hertz
![Plot showing two waves, one with lower frequency labelled 440 Hz and another with higher frequency labelled 880 Hz](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/media/images/HERTZ.gif?itok=eFeoPp44)
Detailed Description
Plot showing 440 Hertz and 880 Hertz. Hertz (Hz) is a unit of measurement named in honor of Heinrich Hertz, the German physicist who in 1887 first produced electromagnetic waves. Expresses the frequency in cycles per second; 1 Hz = 1 cycle of rise and fall of a wave per second .