Final answer:
The SI unit of frequency, the hertz (1 Hz), is named after German physicist Heinrich Hertz, who confirmed the existence of electromagnetic waves and their travel at the speed of light.
Step-by-step explanation:
The SI unit of frequency is named after the German physicist Heinrich Hertz, who was instrumental in proving the existence of electromagnetic waves. Hertz conducted experiments that confirmed these waves travel at the speed of light and was able to calculate their propagation speed using the equation v = fλ (where v is the velocity of the wave, f is its frequency, and λ is its wavelength). Through his work on electromagnetic wave phenomena, including reflection, refraction, and interference patterns, Hertz lent his name to the SI unit for frequency, which is called the hertz (1 Hz = 1 cycle/s).