Question

In a typical fission reaction, the nucleus is split into two middle-weight nuclei of unequal masses. Which of the two (heavier or lighter) has greater kinetic energy? Which one has greater liner momentum?

Answer 1

Kinetic Energy (K.E.):

• The total kinetic energy released is the same for both nuclei together (from conservation of energy).

• But the lighter nucleus moves faster because the same amount of force acts on both, and lighter mass means higher acceleration.

• Since K.E. = `1/2` mv², for the same momentum, the lighter particle has higher velocity and hence greater kinetic energy.
• Therefore, the lighter fragment has greater kinetic energy.

Linear Momentum:

• According to law of conservation of momentum, the total momentum before and after fission must be equal (initial momentum = 0).

• Thus, the two nuclei recoil with equal and opposite momenta.

• Therefore, both nuclei have equal magnitudes of linear momentum.