Assume you're looking for a new particle X by studying positron colliding with electrons in a particle accelerator. It is believed that the new particles rest mass is 250 MeV/c^2 and it is hoped to be produced by the reaction
e^+ + e^- --> X + γ
were e^+ collides with e^- from opposite directions with the same velocity.
How much energy requires to accelerate the positron and the electrone to such velocity that the reaction is possible?
(Note that the energy of the photon can be set to 0 just at the limit to when the reaction is possible)
The positron rest mass is 0.511 MeV/c^2.
The electrone rest mass is 0.511 MeV/c^2.
Answer in MeV.
e^+ + e^- --> X + γ
were e^+ collides with e^- from opposite directions with the same velocity.
How much energy requires to accelerate the positron and the electrone to such velocity that the reaction is possible?
(Note that the energy of the photon can be set to 0 just at the limit to when the reaction is possible)
The positron rest mass is 0.511 MeV/c^2.
The electrone rest mass is 0.511 MeV/c^2.
Answer in MeV.
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This is simple but awkward to explain. Here goes.
Total energy in = total energy out
Total energy in = rest mass energies of electron and positron + their kinetic energy
We are being asked to find the kinetic energy of particles (call this E). This is the energy required to accelerate the positron and the electron.
Total energy out = rest mass of X + kinetic energy of X + energy of photon
We know rest mass of X = 250 MeV/c^2.
To find the minimum value for E we take both kinetic energy of X and energy o photon as zero.
Total energy in = total energy out
0.511 + 0.511 + E = 250 (really, this is all you need to write down)
E = 250 - (0.511+0.511)
= 249MeV to 3 significant figures
Total energy in = total energy out
Total energy in = rest mass energies of electron and positron + their kinetic energy
We are being asked to find the kinetic energy of particles (call this E). This is the energy required to accelerate the positron and the electron.
Total energy out = rest mass of X + kinetic energy of X + energy of photon
We know rest mass of X = 250 MeV/c^2.
To find the minimum value for E we take both kinetic energy of X and energy o photon as zero.
Total energy in = total energy out
0.511 + 0.511 + E = 250 (really, this is all you need to write down)
E = 250 - (0.511+0.511)
= 249MeV to 3 significant figures
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I believe A is not the answer because as far as sound goes, sound waves iirc can cancel each others waves do not synch. And light can also cancel out (as seen by the dark slits in Youngs slits experiments"