Question

Period
Date
Name
Ohm's Law
Answer the following questions. Show your work.
1. What is the current through a wire that has a resistance of 30 ohms if the voltage is 45 volts?
2. What is the current flowing through a wire if the resistance of the wire is
20 ohms and the voltage is 40 volts?
3. A current of 0.5 amperes flows through a wire. What is the wire's resistance if the voltage is 50 volts?
4. What is the resistance of an electric frying pan that draws 12 amperes of current when connected to a 120 volt circuit?
5. If your skin were very moist so that your resistance was only 1000 ohms, and you touched the terminals of a 24 volt battery, how much current would you draw?
6. If a toaster is plugged into a 110 volt circuit, and has a resistance of 12 ohms, what is the current?
7. What is the voltage on a circuit that has 3 ohms of resistance and draws
4 amperes of current?
8. If your portable stereo uses 0.75 amperes of current and has 8 ohms of resistance, what voltage of battery does it use?
9. What is the resistance of a light bulb that draws 0.5 amperes on a 120
volt circuit?
10. A circuit in the telephone office pushes 4.8 amps across a 10 ohm resistor. What is the potential difference?
11. The current in a hair dryer is 5.5 amperes, and the resistance is 20 ohms. What should the voltage of the circuit you plug it into be?
12. If you have a radio that uses 9 volts of battery to power it, and it's current is 0.5 amps, what is the , resistance of the radio?
13. If your flashlight has a resistance of 2 ohms when used with a 3 volt battery, what is it's amperage?
14. If the current in an electronic device is 11 amps on a 120 volt circuit, what is it's resistance?

Answers

GPT-4o mini
To answer the questions based on Ohm's Law, we use the formula:

\[ V = I \cdot R \]

Where:
- \( V \) = voltage (volts)
- \( I \) = current (amperes)
- \( R \) = resistance (ohms)

We can rearrange Ohm’s Law into two other forms depending on what we need to find:

1. **To find current (I)**:
\[ I = \frac{V}{R} \]

2. **To find resistance (R)**:
\[ R = \frac{V}{I} \]

Now, let's solve each problem:

1. **Current through a wire (30 ohms, 45 volts)**:
\[ I = \frac{V}{R} = \frac{45 \text{ volts}}{30 \text{ ohms}} = 1.5 \text{ A} \]

2. **Current through a wire (20 ohms, 40 volts)**:
\[ I = \frac{V}{R} = \frac{40 \text{ volts}}{20 \text{ ohms}} = 2 \text{ A} \]

3. **Resistance of the wire (0.5 A, 50 volts)**:
\[ R = \frac{V}{I} = \frac{50 \text{ volts}}{0.5 \text{ A}} = 100 \text{ ohms} \]

4. **Resistance of an electric frying pan (12 A, 120 volts)**:
\[ R = \frac{V}{I} = \frac{120 \text{ volts}}{12 \text{ A}} = 10 \text{ ohms} \]

5. **Current drawn from a 24 volt battery (1000 ohms)**:
\[ I = \frac{V}{R} = \frac{24 \text{ volts}}{1000 \text{ ohms}} = 0.024 \text{ A} \text{ (or 24 mA)} \]

6. **Current through a toaster (110 volts, 12 ohms)**:
\[ I = \frac{V}{R} = \frac{110 \text{ volts}}{12 \text{ ohms}} \approx 9.17 \text{ A} \]

7. **Voltage on a circuit (3 ohms, 4 A)**:
\[ V = I \cdot R = 4 \text{ A} \cdot 3 \text{ ohms} = 12 \text{ volts} \]

8. **Voltage of the battery for a stereo (0.75 A, 8 ohms)**:
\[ V = I \cdot R = 0.75 \text{ A} \cdot 8 \text{ ohms} = 6 \text{ volts} \]

9. **Resistance of a light bulb (0.5 A, 120 volts)**:
\[ R = \frac{V}{I} = \frac{120 \text{ volts}}{0.5 \text{ A}} = 240 \text{ ohms} \]

10. **Potential difference in a circuit (4.8 A, 10 ohms)**:
\[ V = I \cdot R = 4.8 \text{ A} \cdot 10 \text{ ohms} = 48 \text{ volts} \]

11. **Voltage of the circuit for a hair dryer (5.5 A, 20 ohms)**:
\[ V = I \cdot R = 5.5 \text{ A} \cdot 20 \text{ ohms} = 110 \text{ volts} \]

12. **Resistance of the radio (9 volts, 0.5 A)**:
\[ R = \frac{V}{I} = \frac{9 \text{ volts}}{0.5 \text{ A}} = 18 \text{ ohms} \]

13. **Amperage of a flashlight (2 ohms, 3 volts)**:
\[ I = \frac{V}{R} = \frac{3 \text{ volts}}{2 \text{ ohms}} = 1.5 \text{ A} \]

14. **Resistance of an electronic device (11 A, 120 volts)**:
\[ R = \frac{V}{I} = \frac{120 \text{ volts}}{11 \text{ A}} \approx 10.91 \text{ ohms} \]

This concludes the calculations based on the questions provided. If you need further clarification or additional assistance, feel free to ask!