Nuclei

Concept:

Step 1: Nuclear radius
Distance when touching:

Step 2: Substitute values
Approximation gives: Conclusion:

Concept: Conservation of momentum.

Step 1: Masses

Step 2: Velocity

Step 1: Mass number change
Each reduces mass by 4:

Step 2: Atomic number change
4 reduce Z by : To reach 83: Conclusion:

Step 1: Understanding the Concept:
The biological effectiveness of radiation depends on Relative Biological Effectiveness (RBE) and quality factor. Alpha particles have a much higher quality factor than gamma rays.
Step 2: Detailed Explanation:
Both deliver 1 gray (same absorbed energy per kg). -particles are densely ionising: RBE . -rays: RBE . Equivalent dose: . So, 1 Gy of -radiation causes about 20 times more biological damage than 1 Gy of -radiation.
Step 3: Final Answer:
The -radiation causes less serious damage than -radiation for the same absorbed dose.