How can you derive the formula for P using E and I from the equation I = P / E?

The formula for power (P) can be derived directly from the initial equation ( I = \frac{P}{E} ) by rearranging it to isolate P. Starting with the equation ( I = \frac{P}{E} ), you can multiply both sides by E to eliminate the fraction. This gives you ( I \times E = P ).

Therefore, rearranging it leads directly to ( P = EI ). This indicates that power is the product of voltage (E) and current (I), which aligns with Ohm's law and the principles of electrical circuits.

In this derivation, the concept of multiplying voltage by current to determine power is a foundational principle in electrical engineering. The units also confirm that voltage (volts) multiplied by current (amperes) results in power measured in watts, making this relationship not only mathematically valid but physically meaningful in the context of electrical systems.