AP Physics 1: Voltage Divider Questions and Answers

📚 Quick Study Guide

• ⚡ A voltage divider is a simple circuit that reduces a large voltage into a smaller one.
• 📐 It uses series resistors to create the desired voltage drop.
• 💡 The output voltage ($V_{out}$) is determined by the ratio of the resistors: $V_{out} = V_{in} * \frac{R_2}{R_1 + R_2}$, where $R_2$ is the resistor across which you're measuring the output voltage.
• 🔑 Key assumptions: The current drawn by the load connected to $V_{out}$ is negligible compared to the current through the resistors $R_1$ and $R_2$.
• 📝 The voltage across each resistor is proportional to its resistance (Ohm's Law).

🧪 Practice Quiz

1. A voltage divider circuit has two resistors, $R_1 = 100 \Omega$ and $R_2 = 200 \Omega$, connected in series with a 9V battery. What is the voltage across $R_2$?
   1. 3V
   2. 4.5V
   3. 6V
   4. 9V
2. In a voltage divider, if $R_1 = R_2$, what fraction of the input voltage appears across $R_2$?
   1. 1/4
   2. 1/3
   3. 1/2
   4. 2/3
3. A voltage divider is designed to provide an output voltage of 3V from a 12V source. If $R_1 = 300 \Omega$, what value of $R_2$ is needed?
   1. 50 \Omega
   2. 75 \Omega
   3. 100 \Omega
   4. 150 \Omega
4. Which of the following changes will increase the output voltage of a voltage divider?
   1. Increasing $R_1$
   2. Decreasing $R_1$
   3. Increasing the input voltage
   4. Both B and C
5. A voltage divider has $V_{in} = 10V$, $R_1 = 400 \Omega$, and $R_2 = 100 \Omega$. What is $V_{out}$?
   1. 1V
   2. 2V
   3. 2.5V
   4. 8V
6. What is the primary purpose of a voltage divider circuit?
   1. To amplify voltage
   2. To reduce voltage
   3. To increase current
   4. To regulate power
7. A voltage divider circuit consists of a 24V source and two resistors, $R_1$ and $R_2$. If the voltage across $R_2$ is 8V, what is the voltage across $R_1$?
   1. 4V
   2. 8V
   3. 12V
   4. 16V