Question

The minimum distance reached by an alpha particle approaching a positively charged nucleus before being turned back is called the:

Options

• Nuclear boundary radius

• Distance of closest approach

• Mass number

• Radius constant

Answer 1

During Rutherford-type scattering, the electrostatic repulsion momentarily stops the alpha particle at a minimum distance before it moves away. This minimum distance is called the distance of closest approach, and it sets an upper limit on the nuclear size.