A neutron travelling with a velocity v and kinetic energy E has a perfectly elastic head-on collision with a nucleus of an atom of mass number A at rest. The fraction of total energy retained by the neutron is approximately

\[{{\left[ \left( A+1 \right)\left( A-1 \right) \right]}^{2}}\]

\[{{\left[ \left( A-1 \right)\left( A+1 \right) \right]}^{2}}\]

\[{{\left[ \left( A-1 \right)/A \right]}^{2}}\]

\[{{\left[ \left( A+1 \right)/A \right]}^{2}}\]

A neutron travelling with a velocity v and kinetic energy E has a perf

1.	A neutron travelling with a velocity v and kinetic energy E has a perfectly elastic head-on collision with a nucleus of an atom of mass number A at rest. The fraction of total energy retained by the neutron is approximately
A.	\[{{\left[ \left( A-1 \right)\left( A+1 \right) \right]}^{2}}\]
B.	\[{{\left[ \left( A+1 \right)\left( A-1 \right) \right]}^{2}}\]
C.	\[{{\left[ \left( A-1 \right)/A \right]}^{2}}\]
D.	\[{{\left[ \left( A+1 \right)/A \right]}^{2}}\]
Answer» B. \[{{\left[ \left( A+1 \right)\left( A-1 \right) \right]}^{2}}\]