The wavelengths and frequencies of all the sections of the em waves were required knowledge in my high school physics course.
Besides, these days everyone has a laser, and you can remember its wavelength. (My green one is 531 nm.)
The wavelengths and frequencies of all the sections of the em waves were required knowledge in my high school physics course.
Besides, these days everyone has a laser, and you can remember its wavelength. (My green one is 531 nm.)