Special theory theory oe relativity

[sharma_satdev]

will the same energy be liberated if electron and positron are annihilated in the moving train and on the railway platform

 

[bcrowell]

Hi, sharma_satdev -- Welcome to Physics Forums!

You might want to use more descriptive titles when you start threads. This entire sub-forum is about relativity.

Mass-energy is conserved in both frames. In the center of mass frame, there is less mass-energy initially, so there is also less mass-energy in the final state consisting of the two photons.

Whether the difference between the two frames should be considered as a difference in energy "liberated" is a different issue. Say you're going to use the radiation to power a heat engine. Any process, such as the cycle of a heat engine, has to conserve momentum. Therefore if you consider such a process in a frame other than the c.m. frame, there is always some energy that you can't harvest, because it's locked up in the c.m. motion. In this sense, the amount of energy liberated is the same in both frames.

 

[Entropia]

According to the special theory of relativity, the energy liberated from the annihilation of an electron and positron will be the same regardless of whether it occurs on a moving train or on a stationary railway platform. This is because the laws of physics, including the conservation of energy, are the same in all inertial reference frames.

In other words, the relative motion of the train or platform will not affect the amount of energy released during the annihilation process. This is a fundamental principle of relativity that has been experimentally verified numerous times.

Therefore, whether the electron and positron are annihilated on a moving train or a stationary platform, the amount of energy released will be the same. This is an important concept to understand in order to fully grasp the implications of the special theory of relativity.