Energy loss in the doppler effect?

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SUMMARY

The discussion centers on the energy changes associated with electromagnetic (EM) waves as described by the Doppler effect. It establishes that the energy of an EM wave, calculated using the formula E = h x f (where h is Planck's constant and f is frequency), is indeed reference frame dependent. When a light-emitting body moves toward or away from an observer, the observed frequency—and thus the energy—changes. The conversation raises critical questions about the source of this gained or lost energy, particularly in relation to classical mechanics and kinetic energy measurements from different reference frames.

PREREQUISITES
  • Understanding of electromagnetic wave properties and the equation E = h x f
  • Familiarity with the Doppler effect in physics
  • Basic knowledge of reference frames in classical mechanics
  • Concept of kinetic energy and its calculation
NEXT STEPS
  • Research the implications of the Doppler effect on energy conservation in physics
  • Explore the relationship between frequency shifts and energy changes in moving sources
  • Study reference frame transformations in classical and relativistic physics
  • Examine case studies involving kinetic energy measurements from different observers
USEFUL FOR

Physicists, students studying wave mechanics, and anyone interested in the implications of the Doppler effect on energy and reference frames.

p.tryon
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If the energy of an EM wave = h x f
and when a light emitting body (of a particular power) is moving toward or away from the observer the observed frequency changes, does the energy change?
If so where does the gained or lost energy come from?
 
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Energy, is of course, reference frame dependent. Consider the classical scenario of two cars traveling towards each other along a road, you are sat in one car. Each car is traveling at 30mph relative to an observer who is stood stationary on the road.

Now, if you (sat in your car) 'measure' the kinetic energy of the other car is it going to be the same as if the stationary observer 'measures' the kinetic energy of the other car?
 

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