A nucleus of uranium decays at rest into nuclei of thorium and helium. Then :

Options

A. the helium nucleus has less kinetic energy than the thorium nucleus
B. the helium nucleus has more kinetic energy than the thorium nucleus
C. the helium nucleus has less momentum thanthe thorium nucleus
D. the helium nucleus has more momentum than the thorium nucleus.

Answer

B

Explanation

`._(92)U^(238) to ._(90)Th^(234)+._(2)He^(4)`
Momentum conservation
`implies| vecp_(Th)|=|vecp_(He)|=p`
Kinetic energy `K=(p^(2))/(2m)`
`Kprop(1)/(m)`
`m_(He) lt m_(Th)`
`impliesK_(He) gt K_(Th)`