Can someone please explain the origin of absorption and emission spectra. My teacher skipped it and i have no idea what they are or what the difference is.
Can someone please explain the origin of absorption and emission spectra. My teacher skipped it and i have no idea what they are or what the difference is.
Any help is much appreciated
Thanks
Emission Spectra • Hot gasses produce line emission spectra • If a gas is heated, the electrons move to higher levels. • As they fall back down to ground state, they emit photons, producing line emission spectra with a black background with bright lines. • Each line corresponds to a particular wavelength of light emitted by the source. • Since only certain photon energies can be emitted, you only get the corresponding wavelengths.
Absorption Spectra • Cool gasses remove certain wavelengths from the continuous spectrum to produce an absorption spectrum • At low temperatures, most of the electrons will be at ground states. • Photons of the correct wavelengths are absorbed by the electrons to excite them to a higher energy level. • These wavelengths are then missing from the continuous spectrum when it comes from the gas • When looking at the sun, we do not see a full spectrum, this is because the light emitted by the sun must travel through the cooler outer layers of the sun’s atmosphere, as a result certain wavelengths are filtered out
Does hot gas just randomly get really excited and emit a photon? As in, the rate of photon emission is randomised?
Also, which way around do Light dependant resistors and Heat dependant resistors resist? eg. do LDRs resist when lots of light are falling on them, or when no light is falling on them?
Electrons are normally in the ground state, we say the electrons are in a excited state when they move up to a higher energy level.
can someone explain this to me: i have heard somewhere that current always stays the same in a circuit and never gets used up. but in some questions and diagrams it shows different currents and ... in confusing
can someone explain this to me: i have heard somewhere that current always stays the same in a circuit and never gets used up. but in some questions and diagrams it shows different currents and ... in confusing
It stays the same in a series circuit but it splits up in a parallel circuit.
Kirchoff's first law: "The sum of the currents entering a point = the sum of the currents leaving that point".
So in other words if you have a circuit that then splits into 2, if it had 10A before then it is impossible for them both to have 10A after splitting as this would break Kirchoff's first law.