Electron present in ______ orbit cannot lose its energy.

Answer

**Step-by-Step Solution:**

1. **Understanding Atomic Structure**: Atoms consist of a nucleus surrounded by electrons that occupy different energy levels or shells. These shells are often referred to as orbits.

2. **Identifying Electron Energy Levels**: Electrons can occupy various energy levels, with the first shell being the closest to the nucleus and subsequent shells being further away.

3. **Energy Loss in Electrons**: When an electron transitions from a higher energy level (shell) to a lower one, it releases energy. This is often observed when electrons move from outer shells to inner shells.

4. **The First Orbit's Stability**: The first orbit (or shell) is unique because electrons in this shell do not have the capacity to lose energy. If they were to lose energy, they would spiral into the nucleus, which is not physically feasible as it would lead to the collapse of the atom.

5. **Conclusion**: Therefore, the electron present in the **first orbit** cannot lose its energy.

**Final Answer**: Electron present in **first** orbit cannot lose its energy.

---