What is the electric power used by an appliance if the current is 2 a and the voltage is 50 volts? show work and include all units

Both the answers from "Big D" and "N9KXF" are correct, but not complete. There is one aspect that needs to be remembered for AC power - the phase relationship between the voltage and current. 

For AC power, the more complete equation for power is P = V * I * cosx, where x is the phase angle between voltage and current. 

If the phase angle between voltage and current is 90 degrees, then even though current may be flowing, the total power over a cycle would be zero. Reactive elements like inductors and capacitors have a 90degree phase relationship between voltage and current. They do not "dissipate" energy. They store energy and give it back during different parts of the AC cycle.