Question

A camcorder has a power rating of 16 watts. If the output voltage from its battery is 9 volts, what current does it use?

Answer 1

Because of the parameters that we are given in the question, the right current formula that should be used for this physics problem is:
I = P/V
Where:
I = Current
P = Power  and 
V = Voltage
From the question, we are told that:
P = 16 W
V = 9 V
Thus, current = P/V = 16/9 = 1.78
Therefore, The current used by the camcorder is 1.8 Amphere.