The atomic hydrogen emits a line spectrum consisting of various series. Which series of hydrogen ato

Q: Why is only the Balmer series visible?

The human eye can only detect light with wavelengths between roughly 400 nm and 700 nm. The energy differences for transitions ending at $n=2$ (Balmer series) perfectly produce photons within this specific wavelength range. Transitions to $n=1$ have too much energy (UV), and transitions to $n=3$ or higher have too little energy (IR).

Q: Does the Lyman series have higher or lower energy than the Balmer series?

The Lyman series has much higher energy. The energy gap between any higher state and the ground state ($n=1$) is significantly larger than the gap to the first excited state ($n=2$). Higher energy means shorter wavelength, which is why Lyman is in the Ultraviolet region.

Q: What happens if an electron drops to $n=5$?

Transitions ending at $n=5$ make up the Pfund series. Because the energy levels get closer together the further you go from the nucleus, the energy released in these transitions is very small, placing the Pfund series deep in the Infrared region.

Q: Can an electron jump upwards instead of falling down?

Absolutely! If a hydrogen atom absorbs a photon with the exact right amount of energy, the electron will jump to a higher energy level. This creates an absorption spectrum, which looks like a continuous rainbow with dark lines missing where the light was absorbed.

Q: Are there series beyond the Pfund series?

Yes, there are. For example, transitions ending at $n=6$ are called the Humphreys series. However, as $n$ increases, the energy gaps become incredibly tiny, so these photons have very long wavelengths, falling into the far-infrared and microwave regions.

Question

The atomic hydrogen emits a line spectrum consisting of various series. Which series of hydrogen atomic spectra is lying in the visible region ?

Options:

(A) Brackett series

(B) Paschen series

(C) Lyman series

(D) Balmer series

Sigma Percentile · Accepted Answer

### The Symphony of the Hydrogen Atom

Imagine you are looking at a hydrogen atom. It seems simple—just one proton and one electron. But when you give that electron some energy, it jumps to a higher orbit. It doesn't stay there forever, though. Eventually, it falls back down, and when it does, it releases that borrowed energy as a tiny packet of light called a photon.

Depending on how far the electron falls, the photon will have a specific amount of energy, and therefore, a specific color or wavelength. This creates a beautiful barcode of light known as an emission spectrum. Let's break down the different series of lines in this spectrum.

### The Invisible Extremes: Lyman and Paschen

When an electron falls all the way down to the absolute lowest energy level, the ground state ($n=1$), it releases a massive burst of energy. This massive energy drop corresponds to very short wavelengths. These transitions make up the **Lyman series**. Because the energy is so high, these photons are entirely in the **Ultraviolet (UV)** region. Our eyes cannot see them.

On the other end of the spectrum, what if the electron only falls down to the third orbit ($n=3$) or the fourth orbit ($n=4$)? These are known as the **Paschen** and **Brackett** series, respectively. The energy gaps between these higher orbits are much smaller. Smaller energy means longer wavelengths, pushing these photons into the **Infrared (IR)** region. Again, completely invisible to the human eye.

### The Sweet Spot: The Balmer Series

Now, let's look at the Goldilocks zone. What happens when an electron falls from a higher orbit down to the first excited state ($n=2$)?

This specific set of transitions is called the **Balmer series**. The energy gaps here are just right—not too big, not too small. The photons emitted during these drops have wavelengths that fall perfectly between $400 	ext{ nm}$ and $700 	ext{ nm}$. This is the exact range of the **Visible light spectrum**!

When an electron drops from $n=3$ to $n=2$, it emits a red photon. From $n=4$ to $n=2$, it emits a cyan photon. These are the beautiful, glowing lines you can actually see in a laboratory when you excite hydrogen gas. Therefore, the Balmer series is the only series of the hydrogen atomic spectrum that lies in the visible region.

Animated Solution for Physics - Atoms: The atomic hydrogen emits a line spectrum consisting of various series. Which series of hydrogen atomic spectra is lying in the visible region ?

Select Answer:

Visualized Solution

Hydrogen Emission Spectrum

Lyman Series

Balmer Series

Paschen and Brackett Series

Conclusion

The Sigma Insight: Bohr Model and Hydrogen Spectra

The Symphony of the Hydrogen Atom

The Invisible Extremes

The Sweet Spot

Similar Questions

Some energy levels of a molecule are shown in the figure. The ratio of the wavelengths $r = \frac{λ _{1}}{λ _{2}}$ is given by