How can we calculate the number of electrons per second flowing through a wire in a circuit?

The number of electrons per second flowing through a wire in a circuit can be calculated from a known current value. Current is measured in amperes (Ampere, A), defined as 1 Coulomb (C) of charge flowing through a cross section of a wire per second. We know that the charge of 1 coulomb is equal to about 6.242 x 10^18 electrons.

Calculation formula

• Current (I) : Current is measured in amperes (A) and represents the amount of charge passing through a cross section of a wire per unit time.

• Number of electrons (N) : The number of electrons per second flowing through a section of a wire.

The formula is as follows:

• N= (I x t) /qe

• I is current (unit: ampere, A)

• t is the time (in seconds, s), and in this calculation t=1 second

• qe is the charge of a single electron (unit: coulomb, C), qe≈1.602×10−19 coulomb

The simplified formula is:

N = I / 1.602 x 10-19

Applied to practical circuits

• Measuring current: First of all, you need to use an Ammeter to measure the current value in the circuit.

• Determine the time: In this example, we set the time t=1 second, but if we need to count the number of electrons in other time periods, we need to adjust the time value accordingly.

• Calculate the number of electrons: The measured current value is substituted into the above formula to calculate the number of electrons per second flowing through a section of the wire.

Practical application example

Suppose we need to calculate the number of electrons in an actual circuit with A current of 2 amps (I = 2 A), then:

N=2/1.602×10⁻¹⁹≈1.248×10¹⁹

This means that at a current of 2 amps, approximately 1.248 × 10^19 electrons are flowing through the wire every second.

Matters needing attention

• Accuracy: There may be errors in the actual measurement, so the calculated result may be slightly different from the theoretical value.

• Temperature and material: Differences in temperature and wire material also affect the conduction efficiency of the current, which in turn affects the calculation results.

• Multiple electron streams: there may be multiple electron streams in the actual circuit at the same time, so the total number of electrons also needs to take these factors into account.

Through the above formula and steps, you can calculate the number of electrons per second flowing through a certain section of the wire in the circuit. This is important for understanding current strength and electron flow in circuits.