Friday Physics #15 - Britney Spears Edition

Source: Britney Spears' Guide to Semiconductor Physics. (No, really, it's quite serious, other than the pictures.)

Welcome back to Friday Physics. I'm sure you all know the drill. Ask your out-there physics questions and I'll do my best to have something to say about it.

Please, don't share this (the post OR the answers) to any other sub-blogs, mainpage blogs, etc. I'm only doing this for fun, I don't want the attending headache of trolls and attacks on my qualifications that come with a "wider audience".