What equation correctly relates voltage, current, and resistance when voltage and resistance are known?

• A. I = E x R
• B. I = E/R
• C. I = R/E
• D. I = R x E

Answer: (B)

The correct equation that relates voltage, current, and resistance when voltage and resistance are known is I = E/R. This formula is derived from Ohm's Law, which states that the voltage across an electrical component is equal to the product of the current flowing through it and its resistance.

In this equation, 'I' represents the current in amperes, 'E' represents the voltage in volts, and 'R' represents the resistance in ohms. By rearranging the basic formula of Ohm's Law, you isolate the current 'I' by dividing the voltage 'E' by the resistance 'R'. Therefore, when you know both the voltage applied to a circuit and the resistance of that circuit, you can easily calculate the current flowing through it by dividing the voltage by the resistance.

This understanding of the relationship between voltage, current, and resistance is fundamental in electrical engineering and is crucial for safely working with electrical systems.