A Level Physics Practice Exam

Outside the nucleus, what type of force acts on an alpha particle?

1. Strong nuclear force

2. Electromagnetic force

3. Gravitational force

4. Weak nuclear force

The correct answer is: Electromagnetic force

The force that acts on an alpha particle outside the nucleus is indeed the electromagnetic force. An alpha particle consists of two protons and two neutrons, making it positively charged due to the presence of protons. When it is outside the nucleus, it is primarily influenced by electromagnetic interactions, particularly with the surrounding charged particles. This force is responsible for the repulsion between the alpha particle and other positive charges in its vicinity, while also allowing for attraction to negatively charged particles, such as electrons. As the alpha particle interacts with its environment, the electromagnetic force plays a crucial role in its behavior, trajectory, and interactions with other atoms or particles. The strong nuclear force, while vital within the nucleus for holding protons and neutrons together, does not act appreciably outside of this domain as it operates at very short distances. Gravitational force, although present, is negligible at this scale compared to electromagnetic interactions. Similarly, the weak nuclear force is primarily involved in processes like beta decay within the nucleus and has little effect on the alpha particle outside of it.