icatio 10 full

• When an alpha particle that has a positive charge gets close to the gold nucleus which is also positive, the kinetic energy of the alpha particle will reduce, and its potential energy will increase.

• The distance at which the kinetic energy of the particle becomes zero is called the distance of the closest approach. It is given by,

$\boxed{\mathbf{d}\mathbf{=}\frac{\mathbf{1}}{\mathbf{4}\mathbf{\pi }{\mathbf{\epsilon }}_{\mathbf{0}}}\frac{\mathbf{z}\mathbf{Z}{\mathbf{e}}^{\mathbf{2}}}{\mathbf{K}}}$

Here ε₀ is the permittivity of free space, z is the atomic number of the projectile, Z is the atomic number of the target, e is the charge of the electron, and K is the kinetic energy of the projectile.