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. `132. xx 10^(2) m s^(-1)`
B. `1.32. xx 10^(7) m s^(-1)`
C. `13.2. xx 10^(2) m s^(-1)`
D. `0.13. xx 10^(7) m s^(-1)`

Answer

b

Explanation

`K=(1)/(2) mv^(2)`
`:. V=sqrt((2K)/(m))=sqrt(2(5.82 xx10^(-13) J)/(6.64xx10^(-27)kg))=1.32xx10^(7) ms^(-1)`.