12031 (g) A firearm shall be deemed to be loaded for the purposes of
this section when there is an unexpended cartridge or shell,
consisting of a case that holds a charge of powder and a bullet or
shot, in, or attached in any manner to, the firearm, including, but
not limited to, in the firing chamber, magazine, or clip thereof
attached to the firearm; except that a muzzle-loader firearm shall be
deemed to be loaded when it is capped or primed and has a powder
charge and ball or shot in the barrel or cylinder.
There is nothing in the the law about having the magazine loaded, But however it has been deemed that a magazine is a intricate part of a gun there for it must remain open and exposed so as to not be considered concealed and violate the ca. penal codes. And a welcome to the forums to you a well, its good for anyone with questions to speak up and to ask them remember there are no stupid questions. PLease stop by and read the noobies thread and pullnshot's videos on youtube are also great references.
Also some of the best info to give you is in part's 1 & 2 of the Don't talk to cops series.