A. Electrostatic force of attraction
B. Electrostatic force of repulsion
C. Direct collision
D. None of the above
B. Electrostatic force of repulsion
A beta-minus particle (β⁻) is a fast-moving electron. Both the beta-minus particle and the electrons surrounding an atom carry negative charges.
Because like charges repel, the passing beta-minus particle interacts with an atomic electron through electrostatic repulsion. If it transfers enough energy, the atomic electron escapes, leaving a positively charged ion. This process is called ionization.
Why are the other options incorrect?
- A. Electrostatic attraction: A beta-minus particle and an atomic electron have the same charge, so they repel.
- C. Direct collision: Radiation physics sometimes describes these interactions as collisions. However, the underlying interaction is electromagnetic; a literal mechanical impact is not required. For this question, B is the intended answer.
- D. None of the above: Option B explains the interaction.
Remember: β⁻ particle → negative charge → repels an atomic electron → may cause ionization.
Scientific clarification: This explanation applies to beta-minus particles. Beta radiation also includes positively charged beta-plus particles, called positrons. Specifying β⁻ makes the question more accurate.
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