Question about Fields: B Field Propagation Speed?

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In summary, the conversation discusses the propagation of the B field from a wire after a switch is flipped. It is clarified that the field travels by a wave-type and does not directly propagate from the wire. The B field changes in intensity from 0 to a value, indicating the propagation of an electromagnetic wave from the wire.
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cragar
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I was told that fields don't travel. So if i have a wire with initially no current running and then i flip a switch to start some current, and I am at a distance x from the wire. Is the time lag from the wire at the speed of light before i feel the B field from the wire? Does the B field propagate out from the wire at the speed of light?
Any input will be much appreciated.
 
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The field travels by the wave-type.

We do not say the B field propagate from the wire.
It is said that the B field is changing from 0 to some value in intensity, which is the result of the propagation of electromagnetic wave from the wire after you switched.
 

1. What is the B field propagation speed?

The B field propagation speed refers to the speed at which changes in the magnetic field travel through space. It is an important concept in the study of electromagnetism, as it helps us understand how magnetic fields interact with each other and with other forms of energy.

2. How is B field propagation speed related to electromagnetic waves?

Electromagnetic waves, such as light and radio waves, are made up of oscillating electric and magnetic fields. The speed at which these fields propagate through space is equal to the speed of light, which is approximately 3x10^8 meters per second. Therefore, the B field propagation speed is also equal to the speed of light.

3. Does the B field propagation speed vary in different materials or environments?

Yes, the B field propagation speed can vary depending on the material or environment it is traveling through. In a vacuum, it travels at the speed of light. However, in other materials, such as air or water, it can be slower due to interactions with atoms and molecules. This is why light appears to bend when passing through different substances.

4. How does the B field propagation speed affect everyday technologies?

The B field propagation speed plays a crucial role in many everyday technologies, such as radio and television broadcasting, Wi-Fi, and cellular networks. These technologies rely on the propagation of electromagnetic waves to transmit information over long distances. Understanding the B field propagation speed helps us optimize and improve these technologies.

5. Can the B field propagation speed be measured?

Yes, the B field propagation speed can be measured using various experimental techniques, such as magnetometers and electromagnetic sensors. These devices can detect changes in the magnetic field and measure the speed at which these changes propagate. This information is important for understanding and predicting the behavior of electromagnetic fields in different situations.

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