The speed of electricity through a conductor, such as copper wire, is typically two-thirds the speed of light. The speed of light in a vacuum is about 299,792 kilometers per second. Therefore, the speed of electricity in a conductor can be around 200,000 kilometers per second.

The Calculation

To calculate the time it takes for electricity to travel 1 kilometer, we use the formula:

Time Distance / Speed

Substituting the values:

Time 1 km / 200,000 km/s 0.000005 seconds 5 microseconds

Therefore, it takes approximately 5 microseconds for electricity to travel 1 kilometer in a typical conductor.

Electrical Propagation

Electrical current does not actually move as fast as electrons themselves. Instead, it is the wave of electrical potential that travels through the conductor at nearly the speed of light. This is why in a short circuit, current can flow almost instantaneously once the circuit is completed.

Speed of Electrons vs. Wave Propagation

If you measure the speed of the moving electrons, they travel at about one-hundredth the speed of light. Electrons in copper wires move very slowly compared to the speed at which the electrical signal propagates in the wire.

The actual signal or wave that travels through the wire, carrying the information or the electrical signal, moves at a speed very close to the speed of light. Therefore, it takes very little time for the signal to travel 1 kilometer.

The formula to calculate the time for the wave propagation is:

Time 1 / (Speed of wave)

For a conductor, the speed of the wave is approximately:

Time 1 / (300,000 km/s) 0.0000033 seconds or 3.3 x 10-6 seconds

Thus, it takes about 3.3 microseconds for the wave to travel 1 kilometer.

Electricity and Instantaneous Transmission

Electricity in a closed circuit behaves almost like instantaneous transmission of information. When a potential difference is applied, an electric field is established throughout the circuit almost at the speed of light, causing electrons throughout the circuit to begin drifting and a current to flow almost immediately.

This phenomenon is essential in modern electrical and electronic systems where fast response times are crucial, making the speed of electricity in a conductor a critical factor in various applications from power grids to digital communications.