Interaction of opacity and rgba

I had a question around opacity and rgba and their interaction based on the
CSS3 Color module. Suppose the following style sheet:

span { 
  color: rgba(100%,0,0,0.5);
  opacity: 0.1
}

Does both "alpha" values apply? I.e. would the text inside a span render
with an effective opacity of 0.05 onto its parents element?

- Jacob