I am making a project in which I will be using an arduino to control several servo motors and LED's. And I ll be using a Rqspberry pi to control arduino. They will be connected serially. In this situation, will Pi be able to power the arduino? Because I will power all the motors and external components seperatel from the battery. I will also connect a camera and WIFI Adapter to the Pi. Will it be able to provide this much current? Note: it is arduino mega 2560. If not, then is there anything I can do? Like external power or something?
If you power the Pi via the standard microUSB socket you can feed 2 amps at 5V into the Pi (the current limit is imposed by the 2 amp polyfuse).
The Pi plus wifi adapter plus camera will probably take 750mA. That would leave over an amp for the Mega2560 which is plenty (I'd guess it would draw around 100mA).
You should have no problems.