Questions

Radio waves have much longer wavelengths and lower frequencies than do visible light waves. In contrast, X-rays have much shorter wavelengths and higher frequencies. 

Ultraviolet Light (UV). part of the electromagnetic spectrum that consists of waves with frequencies higher than those of visible light and lower than those of x-rays.

George Washington

Opposite means not identical, not same, not alike, contrast...

Here in the question, the opposite of the word opposite is asked and is opposite of not same , not identical or not alike is same, like, identical,...