Slash chords

Hi all, after some clarification please.
I have been playing the ukulele for a couple months now and trying out a few new songs.
Reading through some tabs, I have seen the chord of C/B (and a few others similar).
I have had a good look around the web and can see that this is a slash chord, but can't seem to find anything suggesting how it should be played or sound when compared to a straight C. I have also tried a straight C chord in its place and it doesnt sound right.
Anyone shed some light for me please?
Thanks all for the help!

Compared to guitar, there are far fewer slash chords you can actually play on the ukulele. This site will show you what slashies are available for uke: http://www.ukulele-chords.com/slashed-chords

In many cases, you will have to find a substitute for the slashie. Have fun!

This should help you, and has C/B as one of the examples.
http://ukulelehunt.com/2007/11/13/playing-guitar-slash-chords-on-the-ukulele/