What Frequency of electromagnetic radiation has a wavelength of 75cm?
It’s around 400 MHz, part of the radio-frequency spectrum probably designated as UHF (ultra-high frequency). It’s a bit low for microwave, which are usually considered to be above at least 1 GHz. The distinctions and divisions are largely historical. Microwave sources and circuits were originally developed for use in radar techniques before and during WWII. At that time the signal was transferred within waveguides, a distinct difference from the techniques used at lower frequencies. Technology employing the high frequency VHF and UHF bands was generally developed for communication purposes, in the first instance for FM radio and TV stations. But the availability of solid state components which can operate efficiently and reliably at these and higher frequencies means that there are now a wide range of associated applications.
