The Nexus 10 shipped with Android 4.2 ("Jelly Bean") as its operating system and is upgradable to Android 5.1 ("Lollipop") since March 9, 2015.
A 9,000 mAh lithium polymer battery powers the Nexus 10, and is reportedly capable of 9 hours of video playback, 90 hours of audio playback, 7 hours of web browsing, and 500 hours (20.8 days) of standby time [REF].