What does "Battery Use" tell and how is it implemented?

I have several questions about "Settings -> About Phone -> Battery Use", mainly because I don't understand what exactly those items mean.

(1) Does "Cell standby" indicate the energy used by the radio communication with the towers when there is no voice/data communication?

(2) What does "Phone idle" indicate?

(3) What does "Android System" indicate, energy used by the OS code execution?

(4) What does "Mediaserver" indicate?

(5) What does "Android Core Apps" indicate?

(6) It also lists energy consumed by individual apps. I'm wondering if those items only include the energy consumed by CPU+RAM+Flash, because the energy used by display+wifi+cell is already listed separately without breakdown to apps. Am I correct?

(7) How does Android measure energy used by individual hardware component? For example, to measure energy used by display, does it measure by voltage and current or just measure by the time the display and/or backlight is turned on? If the latter is the case, how does it handle different hardware?

(8) How does Android measure energy used by CPU/RAM/Flash of each individual process? I guess for CPU, it may use exampling and find how long each process occupies the CPU, just like many performance profilers do. But for RAM and Flash, it seems to be very expensive to measure it on-line.

(9) Is information in "Batter Use" accurate? :-)

Any help would be highly appreciated. Thanks!