Instructions
Answer the questions below to test your understanding of current, electricity, voltage, resistance, and Ohm's Law. Solve the math problems and plot the provided graphs.
Conceptual Questions
1. What is the relationship between voltage (V), current (I), and resistance (R) according to Ohm's Law?
2. Describe what happens to the current in a circuit if the resistance is increased while maintaining a constant voltage.
3. If two resistors are connected in series, how does the total resistance compare to the individual resistances? Explain your answer.
4. What is the difference between direct current (DC) and alternating current (AC)?
Mathematical Problems
5. Calculate the current flowing through a circuit with a voltage of 24 V and a resistance of 6 ohms using Ohm's Law (I = V/R).
6. If a device operates at 120 V and uses 30 W of power, what is the current flowing through the device? (Use the formula P = IV).
7. A circuit contains two resistors, R1 = 8 ohms and R2 = 4 ohms connected in series. Calculate the total resistance.
8. A resistor has a resistance of 10 ohms. If a current of 2 A flows through it, what is the voltage across the resistor? Use Ohm's Law (V = IR).
Graphing
9. Using the data below, plot the graph of current (I) against voltage (V) for a resistor of 5 ohms:
- V (Volts): 0, 5, 10, 15, 20
- I (Amperes): 0, 1, 2, 3, 4
Provide a suitable scale and label the axes:
10. If the voltage across a resistor is doubled, what happens to the current? Provide a written explanation and plot this scenario on the same graph as above.
Answers
1. I = V/R
2. The current decreases.
3. The total resistance is the sum of the individual resistances.
4. DC flows in one direction; AC changes direction periodically.
5. I = 24 V / 6 ohms = 4 A
6. I = P/V = 30 W / 120 V = 0.25 A
7. Total resistance = R1 + R2 = 8 ohms + 4 ohms = 12 ohms
8. V = I * R = 2 A * 10 ohms = 20 V
9 & 10: Graphing will depend on the responses given.