Measuring Light Frequency: Does Newton's Law Apply?

In summary, the conversation discusses the Doppler effect and the relativistic Doppler effect when traveling directly towards or away from a light source at a constant speed. It is mentioned that the classical Doppler effect states that a higher frequency is measured when moving towards a light source and a lower frequency is measured when moving away. The relativistic Doppler effect adds an additional correction to this concept.
  • #1
grounded
85
1
Can anyone tell me if the following is correct?

Traveling directly towards a source of light at some constant speed, we will measure its frequency to be higher (compared to rest frequency) than what we would expect when using Newton’s laws. Just as traveling away from the source, we would measure its frequency to be a little lower than we would expect it to be.

Thanks!
 
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  • #2
grounded said:
Can anyone tell me if the following is correct?

Traveling directly towards a source of light at some constant speed, we will measure its frequency to be higher (compared to rest frequency) than what we would expect when using Newton’s laws. Just as traveling away from the source, we would measure its frequency to be a little lower than we would expect it to be.
Google for "Doppler effect" and "relativistic doppler effect".

The classical Doppler effect says that if you and the light source are moving towards one another (don't think of this as one of them at rest and the other moving) you will measure a higher frequency, and if you and the light source are moving apart you will measure a lower frequency.

Relativity adds an additional correction, the relativistic doppler effect.
 
  • #3
That's what I thought, just wanted to make sure. Thank you...
 

Related to Measuring Light Frequency: Does Newton's Law Apply?

1. What is light frequency and why is it important to measure?

Light frequency refers to the number of times a wave oscillates in one second, measured in Hertz. It is important to measure because it can tell us about the properties of light, such as its energy and wavelength, and can also provide insight into the nature of matter and the universe.

2. How is light frequency measured?

Light frequency can be measured using a device called a spectrometer, which splits light into its various wavelengths and measures their frequencies. This is often done using a diffraction grating or a prism.

3. Does Newton's Law apply to measuring light frequency?

No, Newton's Law does not apply to measuring light frequency. This law only applies to the movement of macroscopic objects, and does not accurately describe the behavior of light and other electromagnetic waves.

4. What other laws or principles are used to measure light frequency?

A more accurate description of the behavior of light is provided by the laws of electromagnetism, specifically Maxwell's equations. These laws govern the behavior of electromagnetic waves, including light, and are used in the development of instruments and techniques for measuring light frequency.

5. Are there any challenges or limitations to measuring light frequency?

One challenge in measuring light frequency is the extremely high speeds at which light travels, making precise measurements difficult. Additionally, some types of light, such as infrared and ultraviolet, are not visible to the human eye and require specialized equipment to measure their frequency.

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