Questions

In making jewels, gold is usually mixed with copper to make it little hard.

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.

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,...

George Washington