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

Options

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

Answer

To determine which inner-orbit jump of the electron corresponds to the third line from the red end in the Balmer series of the hydrogen spectrum, we can follow these steps:

### Step 1: Understand the Balmer Series
The Balmer series refers to the set of spectral lines that result from electron transitions to the second energy level (n=2) in a hydrogen atom. The lines are observed in the visible spectrum.

**Hint:** Remember that the Balmer series involves transitions where the final energy level is n=2.

### Step 2: Identify the Order of Lines
The lines in the Balmer series are numbered based on their wavelength, starting from the longest wavelength (red end) to the shortest wavelength (blue end). The first line corresponds to the transition from n=3 to n=2, the second line corresponds to n=4 to n=2, and the third line corresponds to n=5 to n=2.

**Hint:** The first line is from n=3 to n=2, the second from n=4 to n=2, and the third from n=5 to n=2.

### Step 3: Determine the Third Line
From our understanding of the order of transitions, we can conclude that the third line from the red end corresponds to the transition where the electron jumps from the n=5 level to the n=2 level.

**Hint:** Count the transitions starting from the red end: 1st (n=3 to n=2), 2nd (n=4 to n=2), and 3rd (n=5 to n=2).

### Step 4: Conclusion
Thus, the third line from the red end in the Balmer series corresponds to the electron transition from n=5 to n=2.

**Final Answer:** The correct option is the transition from n=5 to n=2.