The potential force (E) is the product of the current (I) and the resistance (R) and: The power (W) is the product of the voltage (E) and the current (I).
In audio systems, the primary use we make of Ohms law is to find power and voltage values. Current is rarely measured. Typically we deal with either a source or a load.
See Figure 2.
This would mean that the black box was an amplifier because the power went up from 0.25 W to 1.0 W (a 4 to 1 ratio). Our voltage, however, merely doubled.