As far as I know :
<p>whatever</p>
<p>whatever</p>
will get :
watever
watever
There already is a space between paragraphs, Unless the css says otherwise....
And the <br/> is a simple ligne change.
ie
<p>whatever<br/>
whatever</p>
<p>whatever<br/>
whatever</p>
will get:
whatever
whatever
whatever
whatever