# Speed of Current in a coaxial cable

• Kyuubi
In summary, the speed of current in a coaxial cable is typically around 66% of the speed of light, making it faster than other types of cables. It can be increased by using higher quality materials and reducing interference, but is ultimately limited by the laws of physics. The main factors that affect the speed are the type and quality of the cable, signal frequency, and cable length. It is typically measured in terms of velocity factor, with a higher velocity factor indicating a faster speed.
Kyuubi
Homework Statement
Calculate the inductance and capacitance per unit length of a long coaxial cable, and show that the current, or equivalently charge, wave has speed v =1/√(µ0ϵ0) = c which is the speed of light.
Relevant Equations
Maxwell's equation in a vacuum.
Excuse me for not writing them, I'm not familiar with latex and I think I'll only need a conceptual answer. They should be in the photo though.
I've found the inductance and capacitance per unit length in a long coaxial cable. I even clearly see that if I multiply the two, I can get the speed of light. How do I begin to find the current wave and its speed though?

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Could you figure out the wave speed in a string of given tension and density? Maybe you could then use the same approach to model a wave in coax and find analogous equations using capacitance and inductance.

Kyuubi and berkeman

## 1. What is the speed of current in a coaxial cable?

The speed of current in a coaxial cable is typically around 66% of the speed of light, which is approximately 198,900 miles per second or 299,792,458 meters per second.

## 2. How does the speed of current in a coaxial cable compare to other types of cables?

The speed of current in a coaxial cable is faster than the speed of current in twisted pair cables, but slower than the speed of current in fiber optic cables.

## 3. Why is the speed of current in a coaxial cable important?

The speed of current in a coaxial cable is important because it determines the rate at which data can be transmitted through the cable. A faster speed of current allows for quicker data transfer and better overall performance.

## 4. Can the speed of current in a coaxial cable be increased?

Yes, the speed of current in a coaxial cable can be increased by using higher quality materials and improving the design of the cable. However, the speed of current is ultimately limited by the laws of physics.

## 5. Does the length of a coaxial cable affect the speed of current?

Yes, the length of a coaxial cable can affect the speed of current. The longer the cable, the more resistance it will have, which can slow down the speed of current. This is why it is important to use the appropriate length of cable for your specific needs.

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