Effective speed of current is nearly equal to speed of light while order of drift velocity is 10^-⁴. Please explain this contrast
Asked by ashutosh25807
22nd February 2018,
11:33 AM
Answered by Expert
Answer:
When we estimate the drift speed of conduction electrons from known current density and known density of material we get the value of drift speed around 10 cm/h. This gives the wrong impression that when electrical power source and a device to which electrical power to be deleivered are around 1 m apart, it will take around 10 hours for current to reach the device.
What the conducting wire connects the power source to the device is the electrical field (potential difference). when connection is made between the power source and device, the electrical field (potential difference) in power source is connected to the device. This electrical field will travel at speed of light in the coductor. Once the electrical field (potential difference) is established in the device, current starts flow in the device immediately.
Answered by Expert
22nd February 2018,
10:28 PM
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