(a) Define the distance of closest approach. A `alpha` -particle of kinetic energy K is bombarded on a thin gld foil. The distance of the closest approach is `r_(a)`. What will be the distance of closest approach for an `alpha`-particle of double the kinetic energy ?
(b) Show that the radius of the orbit of an electron in hydrogen atoms varies as `n^(2)`, where n is the principal quantum number of the atom.

Explanation

Apply the formula `mvr=(nh)/(2pi)`