The compound unstabel nucleus `._(92)^(236)U` often decays in accordance with the following reaction
`._(92)^(236)U rarr ._(54)^(140)Xe +._(38)^(94)Sr ` + other particles
During the reaction, the uranium nucleus ''fissions'' (splits) into the two smaller nuceli have higher nuclear binding energy per nucleon (although the lighter nuclei have lower total nuclear binding energies, because they contain fewer nucleons).
Inside a nucleus, the nucleons (protonsa and neutrons)attract each other with a ''strong nuclear'' force. All neutrons exert approxiamtely the same strong nuclear force on each other. This force holds the nuclear are very close together at intranuclear distances.
A proton and a neutron are both shot at `100 m s^(-1)` toward a `._6^(12)C` nucleus. Which particle, if either, is more likely to be absorbed by the nucleus?

Options

A. The proton
B. The neutron
C. Both particles are about equally likely to be absorbed,.
D. Neither particle will be absorbed.

Answer

b

Explanation

Once the neutron gets sufficiently clsoe to the nucleus, the strong nuclear force sucks it in. The same reasoning would apply to the proton, except for one thing, the proton feels eletrostatically repelled by the six protons already inside the carbon nucleus. This repulsion prevents a `100 m s^(-1)` proton from getting close enough to the nuleus for the strong force to 'kick in'. Remember, the strong force becomes important only at tiny distance.