which a `U^(238)` nucleus original at rest , decay by emitting an alpha particle having a speed `u` , the recoil speed of the residual nucleus is

Options

A. `-4v//234`
B. `v//4`
C. `-4v//238`
D. `4v//238`

Answer

A

Explanation

Initially -U nucleus was at rest and after decay its part moves in opposite direction

According to conservation of momentum
`4v + 234V= 238 xx 0 rArr V= -(4v)/(234)`