Can i use 12V-1500MA adapter?
Since no-one mentioned this: I believe the arduino uses a linear regulator. This converts the input voltage down to 5V by burning the excess power as heat.
For example, if you supply it with 12V and the arduino draws 100mA on the 5V supply, then the regulator will have 12-5=7V dropout, and it will dissipate 7V*0.1A = 0.7W.
Since it is usually a small SMD device, not fitted with a heat sink, it can't dissipate a lot of power. It will overheat very easily if you draw high current.
Thus if you feed it with 12V the limit will not be the supply current (unless your supply is really wimpy) but the onboard regulator dissipation.
This does not apply if you use a 5V supply, like a 2A cellphone charger, although some components on the board, like the ferrite beads on the +5V line, may object to such high currents.
Anyway, if you want to do high current stuff like servos, motors, long LED strips and the like, power them separately from the supply, and definitely not from the arduino itself. The arduino should control your stuff, light a few LEDs for indication, total maybe 100mA, but it is not designed for power.