Current from Charge
Current as the rate of charge flow.
Formula
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Example
2 C in 1 s = 2 A
How it works
Electric current tells you how much electric charge passes a point each second. The formula I = Q/t comes from defining current as a flow rate: if a larger amount of charge moves in the same time, the current is larger; if the same charge takes longer to move, the current is smaller. One ampere means one coulomb of charge flowing every second.
When to use it
Use this formula when you know the amount of charge transferred and the time it took, and you need to find the current. It is common in basic circuit problems, battery and capacitor questions, and any situation involving charge moving through a wire.
Worked example, step by step
A wire carries 12 coulombs of charge in 3 seconds. I = Q / t I = 12 C / 3 s I = 4 C/s I = 4 A So the current is 4 amperes.
Common mistakes to avoid
- Mixing up charge and current: charge is measured in coulombs, current in amperes
- Forgetting to divide by time, or using the wrong time units
- Using the formula backwards when asked to find charge or time
Did You Know?
Current is simply the rate at which charge flows, like counting cars passing a point on a highway.
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