The alpha particles are

Options

A. High`-` energy electrons
B. Positively charged hydrogen ions
C. High`-` energy `X-` rays radiations
D. Double positively charged helium nuclei.

Explanation

To solve the question "The alpha particles are", we need to analyze the given options and determine which one accurately describes alpha particles.

### Step-by-Step Solution:

1. **Understanding Alpha Particles**:
- Alpha particles are a type of nuclear radiation. They are composed of two protons and two neutrons, which makes them identical to the nucleus of a helium-4 atom.

2. **Analyzing the Options**:
- **Option 1: High energy electrons** - This is incorrect. Electrons are negatively charged and do not match the composition of alpha particles.
- **Option 2: Positively charged hydrogen ions** - This is also incorrect. Hydrogen ions (protons) do not have the same structure as alpha particles.
- **Option 3: High energy X-rays radiations** - This is incorrect. X-rays are a form of electromagnetic radiation and do not consist of particles like alpha particles.
- **Option 4: Double positively charged helium nuclei** - This is correct. Alpha particles are indeed double positively charged and consist of two protons and two neutrons, making them identical to helium nuclei.

3. **Conclusion**:
- Based on the analysis, the correct answer is **Option 4: Double positively charged helium nuclei**.

### Final Answer:
The alpha particles are **double positively charged helium nuclei**.

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