Can energy conservation be violated?

In summary, photons have more energy when they are emitted from a moving train and reflected back. This extra energy is due to the Doppler effect.
  • #1
Ironman1998
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I think energy can be created...i agree that energy is not conserved between different reference frames..but i can show you that energy measured in a single frame may wary... Does photon's energy increase when i emit it from a train which is moving at comparable speed and get it reflected back by a mirror on a platform so that i can catch it again in the train? According to doppler effect the frequency of the photon for an observer standing near the mirror is greater to an observer in the train.So to the observer near the mirror, energy of the photon is greater than the energy observed by an observer in train.Similarly when it gets reflected back and reaches the train its frequency is larger than the initial frequency when observed by an observer in train .So obviously energy of photon is increased without doing any work...please correct me if i am wrong somewhere
 
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  • #2
Ironman1998 said:
I think energy can be created
No it can't.

Ironman1998 said:
So obviously energy of photon is increased without doing any work...please correct me if i am wrong somewhere
The light bounces off the mirror, and there is energy and momentum transfer there. In the frame of the train the mirror is moving towards the train and is slightly slowed by the reflection. Its kinetic energy is carried away by the light.

[Mentors' note: This post has been edited to remove a loose end from when it was moved from another thread]
 
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  • #3
Ironman1998 said:
So obviously energy of photon is increased without doing any work...please correct me if i am wrong somewhere
As @Ibix mentioned, the mirror is the source of the additional energy. Recall that light exerts pressure on a surface. This pressure reduces the speed of the mirror and thereby transfers both energy and momentum to the light. Energy is conserved in this case.
 
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  • #4
Answer to the title question: No.

Follow-up: Do you really think that millions of scientists and engineers over the past hundred years could plausibly have all missed something so obvious?
 

1. Can energy conservation be violated?

No, energy conservation is a fundamental law of physics that states energy cannot be created or destroyed, only transformed from one form to another.

2. Are there any exceptions to the law of energy conservation?

No, the law of energy conservation has been proven to hold true in all observable natural phenomena and has not been violated in any known cases.

3. What about nuclear reactions, do they violate energy conservation?

No, although nuclear reactions involve a significant amount of energy, they still adhere to the law of energy conservation as the total energy before and after the reaction remains the same.

4. Can energy conservation be violated in the quantum realm?

No, even at the smallest scale of quantum mechanics, energy conservation remains a fundamental law. In fact, the principles of quantum mechanics were developed to explain the conservation of energy in microscopic systems.

5. Is it possible for energy to disappear or appear out of nowhere?

No, the conservation of energy dictates that energy cannot be created or destroyed, so it cannot simply disappear or appear out of nowhere. However, it can be transformed from one form to another, which may give the illusion of disappearing or appearing.

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