Yeah. But that's NOT the way to do it:
If you go Mode > CMYK, the image will be converted to the default CMYK working space (set in the color settings), and you will loose any colors that are out of CMYK gamut!
Mode > RGB will then convert the image to your default RGB working space. sRGB in your case. And clipping any colors that are outside sRGB gamut in the process...
If your intended output is for web, I'd use sRGB troughout.


