#AP Physics C: E&M - Resistance, Ohm's Law, and Circuit Elements ⚡

Hey, future physicist! Let's get you prepped for the AP exam with a super-focused review of resistance, Ohm's Law, and circuit elements. This is your go-to guide for a quick, effective study session the night before the test.

#Foundational Concepts: Resistance and Ohm's Law

These are the building blocks of circuit analysis. Understanding them is key to tackling more complex problems. Let's dive in!

#Ohm's Law

• Definition: Ohm's Law describes the relationship between voltage ($V$), current ($I$), and resistance ($R$) in a circuit: $V = IR$

• Voltage ($V$): The electrical potential difference across a component, measured in volts (V).
• Current ($I$): The flow of electric charge, measured in amperes (A).
• Resistance ($R$): The opposition to the flow of current, measured in ohms (Ω).

#Resistivity

• Definition: Resistivity ($ho$) is a material's intrinsic property that measures how strongly it opposes the flow of electric current. It's measured in ohm-meters (Ω⋅m).
• Key Point: Unlike resistance, which depends on the dimensions of the material, resistivity is a property of the material itself.

#Resistance

• Definition: Resistance ($R$) is the measure of how much a material opposes the flow of electric current. It depends on the material's resistivity ($ho$), length ($L$), and cross-sectional area ($A$): $R = \frac{\rho L}{A}$