Ohm's Law is a fundamental principle in the field of electronics and electrical engineering. It states that the voltage (V) across a conductor is directly proportional to the current (I) flowing through it, with the proportionality constant being the resistance (R) of the conductor. The formula for Ohm's Law is:
\[ V = I \cdot R \]
Where:
- \( V \) is the voltage (measured in volts, V)
- \( I \) is the current (measured in amperes, A)
- \( R \) is the resistance (measured in ohms, \(\Omega\))
To find the voltage, we simply use the formula as it is.
Example 1: Voltage in a Household Circuit
Question: A household circuit has a current of 3 amperes flowing through a light bulb with a resistance of 40 ohms. What is the voltage across the light bulb?
Calculation:
Given:
- \( I = 3 \) A
- \( R = 40 \) \(\Omega\)
Using the formula:
\[ V = I \cdot R = 3 \cdot 40 = 120 \text{ V} \]
Result: The voltage across the light bulb is 120 volts.
Example 2: Voltage in a Car Headlight
Question: A car headlight has a current of 2 amperes flowing through it, and its resistance is 6 ohms. What is the voltage across the headlight?
Calculation:
Given:
- \( I = 2 \) A
- \( R = 6 \) \(\Omega\)
Using the formula:
\[ V = I \cdot R = 2 \cdot 6 = 12 \text{ V} \]
Result: The voltage across the car headlight is 12 volts.
Example 3: Voltage in a Smartphone Charger
Question: A smartphone charger has a current of 1.2 amperes flowing through it, and its resistance is 4.2 ohms. What is the voltage across the charger?
Calculation:
Given:
- \( I = 1.2 \) A
- \( R = 4.2 \) \(\Omega\)
Using the formula:
\[ V = I \cdot R = 1.2 \cdot 4.2 = 5.04 \text{ V} \]
Result: The voltage across the smartphone charger is 5.04 volts.
By understanding and applying Ohm's Law, we can easily calculate the voltage across various devices and circuits. This is essential for designing and troubleshooting electrical and electronic systems.
