When B-10 is bombarded by neutrons, a neutron can be absorbed and an alpha paryt

Question

When B-10 is bombarded by neutrons, a neutron can be absorbed and an alpha paryticle emitted. If the B-10 target is stationary, the kinetic energy of the reaction products is equal to the

A) Kinetic energy of the incident neutron

B) total energy of the incident neutron

C) energy equivalent of the mass decrease in the reaction

D) energy equivalent of the mass decrease in the reaction, minus the kinetic energy of the incident neutron

E) energy equivalent of the mass decrease in the reaction, plus the kinetic energy of the incident neutron.

Explanation / Answer

The conservation of total energy E^2 = e^2 + k^2; where E is total energy, e is the mass-energy equivalent, and k is the kinetic energy.

Anyway B + n ---> He + B- so the total energy before absorption comes from the e energy of the target and the neutron, plus the k energy of the neutron, assuming B is stationary.

B lost some mass in sloughing of the alpha and gained the one neutron, so the net loss in 2p and 1n so I call that B-, the B without that mass. And there is the e energy of the 2p and 2n in the He.

So we can find the resulting k by subtracting the equivalent rest masses of both the He and the B- from the TE of the B and n, including the n kinetic energy. The difference with be the total kinetic energy of both He and B-.

And there's your answer E.

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