Question

What are the initial and final mechanical energies, respectively, when an incoming alpha particle momentarily stops near a gold nucleus?

Options

• Initial kinetic energy \[K\] and final electric potential energy \[U\]

• Initial electric potential energy \[U\] and final kinetic energy \[K\]

• Initial and final electric potential energy \[U\]

• Initial and final kinetic energy \[K\]

Answer 1

The incoming alpha particle initially has kinetic energy \[K\]. When it momentarily stops, that energy is the system’s electric potential energy \[U\].