Finding the voltage when the power and current are known is a common requirement in various electrical applications. The relationship between these quantities is straightforward and can be calculated using the formula.
The Formula: \( P = V \cdot I \)
To find the voltage, we rearrange the formula as follows:
\[ V = \dfrac{P}{I} \]
Where:
- \( P \) is the power (measured in watts, W)
- \( V \) is the voltage (measured in volts, V)
- \( I \) is the current (measured in amperes, A)
Example 1: Voltage of a Hair Dryer
Question: A hair dryer uses 1500 watts of power and draws 12.5 amperes of current. What is the operating voltage of the hair dryer?
Calculation:
Given:
- \( P = 1500 \) W
- \( I = 12.5 \) A
Using the formula:
\[ V = \dfrac{P}{I} = \dfrac{1500}{12.5} = 120 \, \text{V} \]
Result: The operating voltage of the hair dryer is 120 volts.
Example 2: Voltage of a Microwave Oven
Question: A microwave oven operates at 1200 watts and draws 10 amperes of current. What is the voltage supply to the microwave oven?
Calculation:
Given:
- \( P = 1200 \) W
- \( I = 10 \) A
Using the formula:
\[ V = \dfrac{P}{I} = \dfrac{1200}{10} = 120 \, \text{V} \]
Result: The voltage supply to the microwave oven is 120 volts.
Example 3: Voltage for a Power Tool
Question: A power tool operates with a power of 600 watts and draws a current of 5 amperes. What is the required voltage?
Calculation:
Given:
- \( P = 600 \) W
- \( I = 5 \) A
Using the formula:
\[ V = \dfrac{P}{I} = \dfrac{600}{5} = 120 \, \text{V} \]
Result: The required voltage for the power tool is 120 volts.
