What is Ohm's Law?
Ohm's Law states that the current (\(I\)) through a conductor between two points is directly proportional to the voltage (\(V\)) across the two points and inversely proportional to the resistance (\(R\)) between them. Mathematically, it is expressed as:
\[ V = I \cdot R \]
Where:
- \(V\) is the voltage (measured in volts, V)
- \(I\) is the current (measured in amperes, A)
- \(R\) is the resistance (measured in ohms, Ω)
Example 1: Calculating Voltage for a Household Appliance
Question: A household toaster draws a current of 8 amperes and has a resistance of 15 ohms. What is the voltage across the toaster?
Calculation:
Given:
- \(I = 8\) A
- \(R = 15\) Ω
Using the formula:
\[ V = I \cdot R = 8 \cdot 15 = 120 \, \text{V} \]
Result: The voltage across the toaster is 120 volts.
Example 2: Determining Voltage for a Car Headlight
Question: A car headlight operates with a current of 5 amperes and has a resistance of 3 ohms. What is the voltage supplied to the headlight?
Calculation:
Given:
- \(I = 5\) A
- \(R = 3\) Ω
Using the formula:
\[ V = I \cdot R = 5 \cdot 3 = 15 \, \text{V} \]
Result: The voltage supplied to the car headlight is 15 volts.
Example 3: Finding Voltage for a Smartphone Charger
Question: A smartphone charger operates with a current of 2 amperes and has a resistance of 6 ohms. What is the voltage across the charger?
Calculation:
Given:
- \(I = 2\) A
- \(R = 6\) Ω
Using the formula:
\[ V = I \cdot R = 2 \cdot 6 = 12 \, \text{V} \]
Result: The voltage across the smartphone charger is 12 volts.
Conclusion
Ohm's Law provides a simple yet powerful formula to calculate the voltage across any electrical component if the current and resistance are known. By applying the formula \(V = I \cdot R\), you can easily determine the voltage for various real-life applications, from household appliances to automotive parts and electronic devices. Understanding and using this fundamental law is essential for anyone working with electrical circuits and systems.
