How much power is delivered by a voltage of 12 volts DC and a current of 2.5 amperes?
Why DC power is simply voltage times current: P = E x I. With 12 volts across the load and 2.5 amperes flowing, P = 12 x 2.5 = 30 watts. This is the basic form of the power equation, the same one that gives P = I squared times R or P = E squared divided by R when you substitute Ohm's law.
Watch out The 4.8 watt choice comes from dividing 12 by 2.5, and 0.208 comes from dividing 2.5 by 12; power uses multiplication, not division. The 14.5 figure is just the two numbers added, which has no physical meaning.
PIE: P = I x E. Multiply volts by amps, never divide.