State Kirchhoff's voltage law.

State Kirchhoff's voltage law.

• A. The sum of products of voltage and resistance around a loop is zero.
• B. The sum of all currents around a loop is zero.
• C. The energy stored in all reactive components around a loop is zero.
• D. The sum of voltages around any closed loop equals zero.

Answer: (D)

Kirchhoff's voltage law says that the sum of all voltage rises and drops around any closed loop in a circuit is zero. This comes from energy conservation: if you travel around a loop and return to your starting point, the net change in electric potential must be zero, so all the increases and decreases balance out. In practice, you can think of it as assigning a sign to each element as you traverse the loop. A battery moving from negative to positive terminal is a voltage rise, while passing through a resistor or other element is a voltage drop (often V = I·R for a resistor). When you add up all those rises and drops along the loop, they cancel to zero. For example, a loop with a battery of V volts and a resistor of resistance R carrying current I gives V (rise) minus I·R (drop) equals zero, which leads to V = I·R. That concrete case shows how KVL works to relate voltages and currents in a circuit. The other statements aren’t correct for this law: summing products of voltage and resistance around a loop isn’t a standard circuit law and doesn’t describe how voltages behave around a loop; summing currents around a loop mixes up Kirchhoff’s current law, which deals with currents at a node, not around a loop; and claiming the energy stored in reactive components around a loop sums to zero contradicts how energy is stored and exchanged in inductors and capacitors.

Kirchhoff's voltage law says that the sum of all voltage rises and drops around any closed loop in a circuit is zero. This comes from energy conservation: if you travel around a loop and return to your starting point, the net change in electric potential must be zero, so all the increases and decreases balance out.

In practice, you can think of it as assigning a sign to each element as you traverse the loop. A battery moving from negative to positive terminal is a voltage rise, while passing through a resistor or other element is a voltage drop (often V = I·R for a resistor). When you add up all those rises and drops along the loop, they cancel to zero.

For example, a loop with a battery of V volts and a resistor of resistance R carrying current I gives V (rise) minus I·R (drop) equals zero, which leads to V = I·R. That concrete case shows how KVL works to relate voltages and currents in a circuit.

The other statements aren’t correct for this law: summing products of voltage and resistance around a loop isn’t a standard circuit law and doesn’t describe how voltages behave around a loop; summing currents around a loop mixes up Kirchhoff’s current law, which deals with currents at a node, not around a loop; and claiming the energy stored in reactive components around a loop sums to zero contradicts how energy is stored and exchanged in inductors and capacitors.