Understand a Conceptual question on Scattering

[claymine]

Homework Statement

Hi I am totally lost here, my answer matches with one of the choice but i think my reasoning is total bs please help me

Relevant Equations

# 19

Homework Statement: Hi I am totally lost here, my answer matches with one of the choice but i think my reasoning is total bs please help me
Homework Equations: # 19

 

[Charles Link]

For this particular repulsive scattering, at closest approach, the kinetic energy of the alpha particle is zero, and all of the kinetic energy has been converted to potential energy. The alpha particle then returns back from where it came=180 degree scattering. For practical purposes, you can assume elastic scattering=no energy losses in computing the distance of closest approach. $\\$ Can you write an expression for the potential energy of the system consisting of the nucleus and the alpha particle? What is the charge of the alpha particle?.

 

[Chandra Prayaga]

What was your reason behind your choice?