A beam of alpha paricles is incident on a target of lead. A particular alpha paticles comes in 'head- on' to a particular lead nucleus and stops `6.50 xx 10^(-14) m` away from the center of the nucleus. (This point is well outside the nucleus.) Assume that the lead nucleus, which has 82 protons, remains at rest. The mass of alpha particle is `6.64 xx 10^(-27)kg`
What initial kinetic energy (in joule and in MeV)did the alpha particle have?

Options

A. `36.3`
B. `0.36`
C. `3.63`
D. `2.63`

Answer

C

Explanation

Apply conservation of energy , `K_(1)+U_(1)=K_(2)+U_(2)`.
`r_(1)= oo` and `U_(1)=0`, and `K_(2)=0`.
From `PCE K_(1)=U_(2)=5.82xx10^(-13)=3.63 MeV`