The formula E1 = Et × R1 / (R1 + R2) is known as which law?

The formula E1 = Et × R1 / (R1 + R2) is known as which law?

• A. Kirchhoff's Law
• B. the Law of Proportionality
• C. Ohm's Law
• D. Watt's Law

Answer: (B)

In a simple series circuit, the same current flows through every component, so the voltage divides in proportion to each resistor’s value. The total current is I = Et / (R1 + R2). The voltage across the first resistor is V1 = I × R1 = Et × R1 / (R1 + R2). This shows that the portion of the total voltage across R1 is directly proportional to R1, which is exactly what the given expression captures. So the idea being tested is the proportional distribution of voltage in a series circuit. This is why the law described as the law of proportionality fits best: voltages in a series network split in proportion to the resistances. The result hinges on using Ohm’s law to relate V, I, and R and on the fact that the current is the same through both resistors. Watt’s law and Kirchoff’s law describe related principles, but they don’t name this specific proportional voltage distribution, and Ohm’s law is the underlying step to derive it.

In a simple series circuit, the same current flows through every component, so the voltage divides in proportion to each resistor’s value. The total current is I = Et / (R1 + R2). The voltage across the first resistor is V1 = I × R1 = Et × R1 / (R1 + R2). This shows that the portion of the total voltage across R1 is directly proportional to R1, which is exactly what the given expression captures. So the idea being tested is the proportional distribution of voltage in a series circuit.

This is why the law described as the law of proportionality fits best: voltages in a series network split in proportion to the resistances. The result hinges on using Ohm’s law to relate V, I, and R and on the fact that the current is the same through both resistors. Watt’s law and Kirchoff’s law describe related principles, but they don’t name this specific proportional voltage distribution, and Ohm’s law is the underlying step to derive it.