A radioactive nuclide generally disintegrates by `alpha`-emission when its N/P ratio is

Options

A. less than 1
B. equal to one
C. equal to 1.2
D. greater than 1.5

Answer

To determine when a radioactive nuclide generally disintegrates by alpha emission based on its neutron-to-proton (N/P) ratio, we can follow these steps:

### Step 1: Understand the N/P Ratio
The N/P ratio is the ratio of neutrons (N) to protons (P) in a nucleus. This ratio is crucial in understanding the stability of a nucleus.

### Step 2: Analyze the Stability of Nuclei
- Nuclei with a low N/P ratio (close to 1) tend to be unstable and may undergo beta decay.
- As the N/P ratio increases, particularly when it exceeds 1, the stability of the nucleus can be affected.

### Step 3: Identify the Role of Alpha Emission
Alpha emission is a type of radioactive decay where an alpha particle (2 protons and 2 neutrons) is emitted from the nucleus. This process typically occurs in heavy nuclei.

### Step 4: Determine the Threshold for Alpha Emission
Research indicates that when the N/P ratio is greater than 1, the tendency for alpha emission increases. This is because heavy nuclei with a high N/P ratio are more likely to undergo alpha decay to achieve a more stable configuration.

### Step 5: Conclusion
Therefore, a radioactive nuclide generally disintegrates by alpha emission when its N/P ratio is greater than 1.

### Final Answer
A radioactive nuclide generally disintegrates by alpha emission when its N/P ratio is greater than 1.

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