I am a high school student and I am very confused in absorption and emission spectrum of gases, for e,g take hydrogen at room temperature for simplicity, so that we can talk in terms of Bohr's model of atom
1)We know that when the white light is passes through it, some of the wavelengths will get absorbed by it and electron will be excited to higher energy level, but we also say that when it will return back it will emit he photon of same wavelength, so my question is would these both happens just one after another? i.e will the electron return just after it? but if that's the case it would re-emit is simultaneously so we shouldn't see the dark lines which we usually see?
2}we also know that the any body at any temperature also radiates and if it is at room temperature most of the radiation will be in infrared region, but in this case we are observing that hydrogen will give the photon of lower wavelengths also like when electron would return back from 1st excited state to ground level it will emit radiation of about 122.5nm which lies in visible range, so how is that possible? it is not in accordance with what we see that all bodies at room temperature mostly radiates in infrared region?
please explain it using simple language, which don't involve so many complicated terms because I am at high school level.