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 was the initial speed of the alpha particle?

Options

A. `1.32xx10^(7)m//s`
B. `13.2xx10^(2)m//s`
C. `0.13xx10^(7)m//s`
D. `132xx10^(2)m//s`

Answer

A

Explanation

`K=1/2mv^(2)` so `v=sqrt(2K)/m=1.32xx10^(7)m//s`