An atom stays in an excited state for about

Options

A. `10mus`
B. `10ms`
C. `10ns`
D. `10s`

Answer

### Step-by-Step Solution:

1. **Understanding Excited State**:
- An atom is in an excited state when one of its electrons absorbs energy and jumps from a lower energy level (or shell) to a higher energy level. This process is known as excitation.

2. **Energy Absorption**:
- For an electron to move to a higher energy level, it must absorb energy that is equal to the difference in energy between the two levels. This energy can come from various sources, such as light.

3. **Stability of Excited State**:
- The excited state is considered unstable. The electron does not remain in this higher energy level for long. It will eventually lose the absorbed energy and return to its original (ground) state.

4. **Duration of Excited State**:
- The time an atom typically stays in the excited state before returning to the ground state is very short. It is generally on the order of nanoseconds.

5. **Conclusion**:
- Based on the information provided, an atom stays in an excited state for about **10 nanoseconds**.

### Final Answer:
An atom stays in an excited state for about **10 nanoseconds**.

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