AP Physics 2 Questions on Ohm's Law: Exam Prep

📚 Quick Study Guide

• ⚡ Ohm's Law: Relates voltage (V), current (I), and resistance (R) in a circuit: $V = IR$.
• 📏 Resistance (R): Measured in ohms ($\Omega$). It's the opposition to the flow of current.
• 🔋 Voltage (V): The electric potential difference, measured in volts (V). It's the 'push' that drives the current.
• 🌊 Current (I): The flow of electric charge, measured in amperes (A).
• 🌡️ Factors Affecting Resistance: Resistance depends on the material's resistivity ($\rho$), length (L), and cross-sectional area (A): $R = \rho \frac{L}{A}$.
• 🔗 Series Circuits: Components are connected end-to-end; the current is the same through each component, and the total resistance is the sum of individual resistances ($R_{total} = R_1 + R_2 + ...$).
• ⎔ Parallel Circuits: Components are connected side-by-side; the voltage is the same across each component, and the reciprocal of the total resistance is the sum of the reciprocals of individual resistances ($\frac{1}{R_{total}} = \frac{1}{R_1} + \frac{1}{R_2} + ...$).

🧪 Practice Quiz

1. What is the voltage across a 4 $\Omega$ resistor if a current of 2 A is flowing through it?
   1. 4 V
   2. 2 V
   3. 8 V
   4. 0.5 V
2. A resistor has a voltage of 12 V across it and a current of 3 A flowing through it. What is its resistance?
   1. 36 $\Omega$
   2. 4 $\Omega$
   3. 9 $\Omega$
   4. 15 $\Omega$
3. If a wire's length is doubled and its cross-sectional area is halved, what happens to its resistance?
   1. It remains the same.
   2. It is halved.
   3. It is doubled.
   4. It is quadrupled.
4. Two resistors, 6 $\Omega$ and 3 $\Omega$, are connected in series. What is the total resistance?
   1. 2 $\Omega$
   2. 9 $\Omega$
   3. 18 $\Omega$
   4. 3 $\Omega$
5. Two resistors, 6 $\Omega$ and 3 $\Omega$, are connected in parallel. What is the total resistance?
   1. 2 $\Omega$
   2. 9 $\Omega$
   3. 18 $\Omega$
   4. 3 $\Omega$
6. A circuit has a voltage source of 9 V and a resistance of 3 $\Omega$. What is the current flowing through the circuit?
   1. 3 A
   2. 27 A
   3. 1/3 A
   4. 6 A
7. Which of the following factors does NOT affect the resistance of a wire?
   1. Length
   2. Cross-sectional Area
   3. Material
   4. Current