Calculating the electric charge when given the voltage and electric energy is a fundamental concept in electrical engineering and physics. This relationship is defined by a simple formula that can be applied in many practical situations.
The Formula: \( E = V \cdot Q \)
To find the electric charge using voltage and electric energy, we rearrange the formula as follows:
\[ Q = \dfrac{E}{V} \]
Where:
- \( E \) is the electric energy (measured in joules, J)
- \( V \) is the voltage (measured in volts, V)
- \( Q \) is the electric charge (measured in coulombs, C)
Example 1: Laptop Battery
Question: A laptop battery stores 36000 joules of energy and operates at 12 volts. What is the charge capacity of the battery?
Calculation:
Given:
- \( E = 36000 \) J
- \( V = 12 \) V
Using the formula:
\[ Q = \dfrac{E}{V} = \dfrac{36000}{12} = 3000 \, \text{C} \]
Result: The charge capacity of the laptop battery is 3000 coulombs.
Example 2: Solar Panel
Question: A solar panel produces 1500 joules of energy at a voltage of 20 volts. What is the amount of electric charge generated?
Calculation:
Given:
- \( E = 1500 \) J
- \( V = 20 \) V
Using the formula:
\[ Q = \dfrac{E}{V} = \dfrac{1500}{20} = 75 \, \text{C} \]
Result: The electric charge generated by the solar panel is 75 coulombs.
Example 3: LED Light
Question: An LED light uses 50 joules of energy and operates at 5 volts. How much charge does it consume?
Calculation:
Given:
- \( E = 50 \) J
- \( V = 5 \) V
Using the formula:
\[ Q = \dfrac{E}{V} = \dfrac{50}{5} = 10 \, \text{C} \]
Result: The LED light consumes 10 coulombs of electric charge.
Conclusion
By using the formula \( Q = \dfrac{E}{V} \), you can easily find the electric charge when the voltage and electric energy are known. This knowledge is essential in designing and managing electrical systems, from everyday devices like laptops and LED lights to renewable energy sources like solar panels. Understanding how to calculate electric charge helps in optimizing performance and ensuring efficient energy usage.
