The sum of all voltage drops in a series circuit: a. is equal to the sum of all voltage drops b. is equivalent to the sum of all voltage drops c. is greater than the applied voltage d. equals the applied voltage
The Correct Answer and Explanation is:
Correct Answer: d. equals the applied voltage
Explanation
In a series circuit, components such as resistors are connected end-to-end, forming a single path for current to flow. A key principle that governs the behavior of voltage in such a circuit is Kirchhoff’s Voltage Law (KVL). This law states that the sum of all electrical potential differences (voltage drops) around a closed loop is equal to the total voltage supplied by the source.
To understand why the correct answer is (d) equals the applied voltage, consider the way energy is used in a circuit. The power source (such as a battery) provides a certain voltage, which represents the electrical energy available per unit charge. As the electric current flows through each component in the series circuit, it encounters resistance and uses up energy. This energy usage is reflected as voltage drops across each resistor or device.
In a series circuit, current remains constant throughout the loop, but the voltage is divided among the components in proportion to their resistance. For example, if you have a 12-volt battery connected in series with three resistors, the voltage drops across the resistors might be 4V, 3V, and 5V respectively. The total of these drops is:
4V + 3V + 5V = 12V
This total matches the applied voltage from the battery, demonstrating Kirchhoff’s Law in action.
Answer choices a and b are redundant and circular (they say the sum equals the sum), and c is incorrect because the total voltage drops can never exceed the applied voltage—this would violate the law of conservation of energy.
Therefore, the correct understanding is that in any series circuit, the total voltage drops equal the applied voltage, making option (d) the correct answer.
