Why does hydrogen gas only emit light of certain colors when electric current is passed through it?

Question

Electrons & Electromagnetic Radiation


I'm just asking for a little help not for an organ or money.

So Please Help. Thank You.
Love Always,
~*Bree!~

Answer 1

Light emitted from a gas is dependent upon electron energy state levels. That is, every atom has a base state for its electon orbits, which they will tend towards by emitting energy in the form of electromagnetic energy (often visible light), when the electron "falls" from a higher orbit to a lower one. Each orbit has a very specific energy level associated with it (and therefore a certain light frequency, or color). There are only a few of these energy states possible for each element, so each orbital change has one of these colors emitted when orbit change is effected.

Conversely, any electron in any element can absorb this exact energy level, and remove this color from its spectograph. Black lines appear at very specific colors, and are unique to each element. This is seen in stellar spectrographs, and is used to find out what they are made of chemically without actually taking a physical sample That is how we know that the sun is mostly made of Hydrogen and Helium.

In the laboratory, it works the same way, as you discovered in ionizing Hydrogen to find the discrete colors it can emit.

Answer 2

actually, this is a great question. This was one of the paradoxes that plagued pre-modern physics, and led to the development of quantum physics.

Hydrogen gas only emits certain wavelengths of light because the energy levels of hydrogen atoms are quantized. Without getting too deep into it, this means that the hydrogen atoms can only be in certain discrete energy states (they can only have certain amounts internal energy).

When electric current is passed through hydrogen, it jumps the energy levels of the atoms up a level or two, and then the atom goes back. When it goes back, it releases a photon. Since it is going beween two distinct energy states, the energy (and therefore the wavelength) is always the same, so you only get a few wavelengths corresponding to jumps between different energy levels.

Answer 3

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RE:
Why does hydrogen gas only emit light of certain colors when electric current is passed through it?
Electrons & Electromagnetic Radiation


I'm just asking for a little help not for an organ or money.

So Please Help. Thank You.
Love Always,
~*Bree!~

Answer 4

Color Of Hydrogen Gas

Answer 5

The electron in the atom can only occupy certain orbits due teh qunatization of the energy of the electron. The energy difference between two levels n1 and n2 is

DE = -13.6(1/n1 - 1/n2) electron volts (n1, n2 =1, 2, 3...) The negative sign indicates the ground state as having a negative potential energy - you have to add 13.6 ev to ionize hydrogen.

Now when an electron goe from an excited state n1, to a lower state n2 < n1, it has to give up energy per the formula above. It does so by emitting a photon. So the photon can only have energies related by the differences of the inverse of two integers. The energy of a photon is related to its wavelength (color) by:

E = hc/wl where h = Planck's constant, c = speed of light and wl = wavelength.

Setting DE = E ---> -13.6(1/n2 -1/n1)*k = hc/wl

wl = hc/(13.6 *k*(1/n1-1/n2)) = hc n1 n2/(13.6 k (n2-n1))

k = 1.6x 10^(-19) J/ev

Since n1, n2 are integers, wl can only take on discrete values hence only certain colors can be emitted (or absorbed) by the atom.