A question on wave nature of EM radiation

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Discussion Overview

The discussion revolves around the relationship between frequency, distance, speed, and time in the context of electromagnetic (EM) radiation. Participants explore how these concepts interconnect, particularly in relation to the speed of light and the implications of different media on this relationship.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant questions how frequency, distance, speed, and time are related in the context of EM radiation, seeking clarification on the relationship.
  • Another participant states that the speed of EM radiation is constant (c) in a vacuum and suggests that time can be calculated by dividing distance by speed.
  • A different participant explains that frequency and wavelength relate to the oscillation of the electromagnetic field, emphasizing that they do not directly affect the time taken for light to travel a distance.
  • One participant notes that the relationship between frequency, wavelength, and speed can be expressed as c = λν, but highlights potential confusion arising from quantum mechanics and the photon model.
  • There is mention of the need to consider the medium through which the EM radiation travels, as this can affect the speed and thus the time calculation.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the relationship between the discussed variables. While some agree on the fundamental principles, others highlight confusion and the need for clarification, indicating that the discussion remains unresolved.

Contextual Notes

Participants note that the answer to the original question depends on the medium through which the EM radiation travels, and there are distinctions between phase and group velocity that may contribute to confusion.

SpaceExplorer
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There is a EM radiation of frequency suppose x Hz.Let it has to travel a distance of y m.Now what's the time required for the radiation to travel the distance?The question seems to be very easy, but my confusion is in how can the frequency,distance,speed and time can be related? Can someone give the relation along with the answer?
 
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v == c
s = ct
f = c / wavelength

Wavelength and frequency have nothing to do with the distance the light travels or the time it takes to get there. The frequency describes the oscillation of the electromagnetic field over time. The "wavelength" of the light is not the physical size of the photon but the distance the photon travels in going through one complete EM cycle.

Imagine a little blob of light moving in a straight line quickly oscillating from red to black to blue to black to red and so forth as it moves. The red and the blue represent the oscillations of the EM field. The wavelength is the distance the blob travels while doing a complete red/blue cycle.
 
hi
electromagnetic radiation speed is c i.e speed of light which is 3.0 x 10 ^8 m/s in air
It does not change except if it is traveling in a different medium
So divide distance y by c , you get the time t
 
Last edited:
SpaceExplorer said:
There is a EM radiation of frequency suppose x Hz.Let it has to travel a distance of y m.Now what's the time required for the radiation to travel the distance?The question seems to be very easy, but my confusion is in how can the frequency,distance,speed and time can be related? Can someone give the relation along with the answer?

As others have written, there's a clean relationship between the frequency, wavelength and speed (c = [tex]\lambda\nu[/tex]). Confusion usually comes in when trying to understand this in terms of quantum mechanics, specifically the photon picture and the idea of refeactive index.

For your question, since you did not give a medium, the answer can't be given. But the general answer is t= c/n *y. Again, sources of confusion exist here, in terms of phase vs. group velocity. But, since you are assuming monochromatic light, there shouldn't be any issues.
 

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