What are the steps to apply Kirchhoff's Loop Rule?
1. Define currents in each branch. 2. Choose a closed loop. 3. Apply the loop rule: $\sum \Delta V = 0$. 4. Account for voltage rises and drops. 5. Solve for unknowns.
How do you determine the sign of a voltage change across a resistor?
If traveling in the direction of the current, the voltage change is negative (voltage drop). If traveling against the current, the voltage change is positive (voltage rise).
How do you determine the sign of a voltage change across a battery?
If traveling from the negative to the positive terminal, the voltage change is positive (voltage rise). If traveling from the positive to the negative terminal, the voltage change is negative (voltage drop).
What is the first step in solving a circuit problem using Kirchhoff's rules?
The first step is to define the currents in each branch of the circuit, assigning a direction to each current.
How do you solve for unknown currents in a circuit once you have applied Kirchhoff's rules?
Solve the resulting system of linear equations using substitution, elimination, or matrix methods to find the values of the unknown currents.
What is the effect of increasing the resistance in a circuit loop?
For a constant voltage source, increasing resistance will decrease the current in the loop, according to Ohm's Law.
What is the effect of a voltage source in a closed loop?
A voltage source provides a potential rise, driving current through the loop and influencing the potential drops across other components.
What happens if the sum of potential differences in a closed loop is not zero?
This violates the conservation of energy, indicating an error in the circuit analysis or an external energy source/sink not accounted for.
What happens to the current if you reverse the polarity of a battery in a loop?
The direction of the current in the loop will reverse, and the voltage drops across resistors will also change direction.
What happens to the brightness of a light bulb (resistor) if the current through it increases?
The brightness of the light bulb increases because the power dissipated by the resistor (light bulb) is proportional to the square of the current ($P = I^2R$).
Define Kirchhoff's Loop Rule.
The sum of all potential differences (voltages) around any closed loop in a circuit must equal zero: $\sum \Delta V = 0$
Define electric potential difference.
The change in electric potential energy per unit charge when a charge moves between two points.
Define electric potential energy.
The energy a charge possesses due to its position in an electric field.
What is a closed loop in a circuit?
A continuous path in a circuit that starts and ends at the same point, allowing current to flow without interruption.
Define voltage drop.
The decrease in electric potential across a circuit element, typically a resistor, due to the energy dissipated as current flows through it.
