Question

In the Rutherford scattering experiment, an alpha particle is aimed directly at a gold nucleus. The distance of closest approach of the alpha particle to the nucleus occurs when:

A) the alpha particle hits the nucleus

B) the alpha particle hits the electron cloud

C) the kinetic energy of the alpha particle is completely transformed to potential energy due to the nuclear force

D) the kinetic energy of the alpha particle is completely transformed to potential energy due to the electric field of the nucleus

E) the kinetic energy of the alpha particle is completely transformed to potential energy due to the electric field of the electrons

Answer 1

The distance of closest approach of two objects is the distance between their centers when they are externally tangent.

In the case of Rutherford scattering, alpha particle actually never hits the nucleus. Hence, A is incorrect.

Diatance of closest approach is the diatance where the kinetic energy of alpha particle is completely transformed to potentual energy due to electric field of nucleus.

Option C is incorrect because nucleur force will convert the gold nucleus into other element. Which does not occur in Rutherford scattering.

Answer= D