In hydrogen spectrum, the third line from the red end corresponds to which one of the following inter-orbit jumps of the electron for Bohr orbits in an atom of hydrogen ?

Options

A. `5 rarr 2`
B. `4 rarr 1`
C. `2 rarr 5`
D. `3 rarr 2`

Explanation

To determine the inter-orbit jump of the electron in the hydrogen atom corresponding to the third line from the red end in the hydrogen spectrum, we will follow these steps:

### Step 1: Understand the Series
The hydrogen spectrum consists of several series, and the visible lines correspond to the Balmer series. The Balmer series involves transitions where the electron falls to the n=2 energy level from higher energy levels (n=3, 4, 5, etc.).

**Hint:** Remember that the Balmer series is the only series that produces visible light.

### Step 2: Identify the Ground State
In the Balmer series, the ground state (final state) is fixed at n=2. The initial state (n2) can be any value greater than 2 (n=3, 4, 5, ...).

**Hint:** The ground state for the Balmer series is always n=2.

### Step 3: Determine the Line Position
The lines in the Balmer series correspond to different transitions:
- The first line (H-alpha) corresponds to the transition from n=3 to n=2.
- The second line (H-beta) corresponds to the transition from n=4 to n=2.
- The third line (H-gamma) corresponds to the transition from n=5 to n=2.

**Hint:** Count the lines starting from the red end (longest wavelength) to identify the transitions.

### Step 4: Identify the Third Line
Since we are looking for the third line from the red end, we need to find the transition that corresponds to this line. As established:
- 1st line: n=3 to n=2 (H-alpha)
- 2nd line: n=4 to n=2 (H-beta)
- 3rd line: n=5 to n=2 (H-gamma)

Thus, the third line corresponds to the transition from n=5 to n=2.

**Hint:** The third line corresponds to the highest energy level that transitions to n=2.

### Final Answer
The third line from the red end in the hydrogen spectrum corresponds to the electron transition from n=5 to n=2.

**Correct Option:** 5 to 2 (Option 1).