Name the source of illumination in electron microscope.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the source of illumination in an electron microscope. This requires knowledge of how electron microscopes function and what they use for imaging.

2. **Identifying the Type of Microscope**: Recognize that there are different types of microscopes. An electron microscope is distinct from optical microscopes because it uses electrons instead of light for imaging.

3. **Source of Illumination in Electron Microscopes**: In an electron microscope, the source of illumination is not light but rather a beam of electrons.

4. **Mechanism of Electron Emission**: The electrons are emitted from a component known as the tungsten filament. This filament is heated to produce a stream of electrons.

5. **Conclusion**: Therefore, the source of illumination in an electron microscope is the beam of electrons emitted from the tungsten filament.

**Final Answer**: The source of illumination in an electron microscope is the beam of electrons emitted from a tungsten filament.

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