If an electron is present in the third orbit of hydrogen atom, maximum number of emission spectral lines will be

Explanation

To determine the maximum number of emission spectral lines for an electron in the third orbit of a hydrogen atom, we can follow these steps:

### Step 1: Understand the Concept of Emission Spectral Lines
Emission spectral lines are produced when electrons transition from a higher energy level to a lower energy level, emitting photons in the process. The number of possible transitions determines the number of spectral lines.

### Step 2: Identify the Formula
The formula to calculate the maximum number of emission spectral lines when an electron is in a given orbit (n) is given by:
\[ \text{Number of spectral lines} = \frac{n(n-1)}{2} \]
where \( n \) is the principal quantum number of the orbit.

### Step 3: Substitute the Value of n
In this case, the electron is in the third orbit, so \( n = 3 \). We can now substitute this value into the formula:
\[ \text{Number of spectral lines} = \frac{3(3-1)}{2} \]

### Step 4: Calculate the Result
Now, we perform the calculation:
\[ = \frac{3 \times 2}{2} = \frac{6}{2} = 3 \]

### Step 5: Conclusion
Thus, the maximum number of emission spectral lines when an electron is present in the third orbit of a hydrogen atom is **3**.

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