AP Physics C: Electricity and Magnetism
Advanced Placement Physics C: Electricity and Magnetism with calculus applications.
Current, Resistance, and Circuits
Electric Current
Electric current is the flow of charge, measured in amperes (A). It’s like water flowing through a pipe, but with electrons moving through a wire!
Resistance
Resistance is how much a material opposes current:
\[ R = \rho \frac{L}{A} \] where \( \rho \) is resistivity, \( L \) is length, and \( A \) is cross-sectional area.
Ohm’s Law
The relationship between current, voltage, and resistance is:
\[ V = IR \]
Series and Parallel Circuits
- Series: Current is the same, voltages add.
- Parallel: Voltage is the same, currents add.
Calculus in Circuits
Charge and current can change with time, so we use derivatives and integrals to analyze RC, RL, and RLC circuits.
Real-World Example
Understanding circuits keeps your phone from overheating and helps engineers design safe power systems.
Examples
Calculating total resistance in a complex network.
Finding current over time as a capacitor charges.
In a Nutshell
Current, resistance, and Ohm’s Law describe how electricity flows and how circuits work.