An alpha particle (He-nucleus) is propelled toward a potassium nucleus (Z = 19). The diameter and energy levels of the nucleus are depicted in the figure below. Initially, the potassium nucleus is in its ground state. However, after the collision, it emits a photon with a wavelength of approximately 64.91 fm. Determine the minimum initial speed of the alpha particle. Hint: Consider the principle of energy conservation while analyzing the alpha particle-nucleus interaction.

• A. 3.32 × 10⁶ m/s
• B. 5.79 × 10⁸ m/s
• C. 4.18 × 10⁷ m/s
• D. 9.12 × 10⁵ m/s

Answer: (C)