Total number of spectral in UV region during transition from ` 5 ^(th)` excited state to `1^(St)` excited state

Options

A. 10
B. 3
C. 4
D. zero

Answer

To solve the question regarding the total number of spectral lines in the UV region during the transition from the 5th excited state to the 1st excited state, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Energy Levels**:
- The 5th excited state corresponds to \( n = 6 \) (since the ground state is \( n = 1 \)).
- The 1st excited state corresponds to \( n = 2 \).

2. **Determine the Transition**:
- The transition is from \( n = 6 \) to \( n = 2 \).

3. **Understand the UV Region**:
- The UV region corresponds to transitions that end at the ground state, which is \( n = 1 \).

4. **Check the Transition Requirements**:
- For spectral lines to be observed in the UV region, the electron must transition to the ground state (\( n = 1 \)).
- In this case, the transition is from \( n = 6 \) to \( n = 2 \), which does not involve the ground state.

5. **Conclusion**:
- Since the transition does not end at \( n = 1 \), there will be no spectral lines in the UV region for the transition from \( n = 6 \) to \( n = 2 \).
- Therefore, the total number of spectral lines in the UV region is **0**.

### Final Answer:
The total number of spectral lines in the UV region during the transition from the 5th excited state to the 1st excited state is **0**.