IIT JEE , AIEEE Forum - Chemistry , Physical Chemistry

catchyash111

Plz xplain me wats

1.Emission and Absorption Spectra

2. Line Spectrum of hydrogen

Plz don't put direct quotes frm d buk ,,, instead plz xplain me !!!!!!!!!

ananth_patri

when light of some freq is incident on atoms...then the electrons jump to next orbitals by using the energy provide....now again whn they come back to their original orbits. they emit enery...this is of diff freq and thus we get spectrun..the elect. absro light and we get absorption spectra which is black lines on a white backgrouund and when e;lect. emit energy we get emission spectra... which is bright lines on black background....rate me if u r satified...

ananth_patri

in these emission spectra and absorption spectra only there are two types like line spectra and band spectra....

dev_22oct

EMISSION SPECTRA: is obtained when the light or radiation from the source is directly analysed by spectroscope.

it could be of 2 type

1) line spectrum

when a light is passed through vapours of NaCl then e- of Na get excited and when the excited e-s come back they emit light which is analysed by spectroscope and we get 2 yellow line at 589nm and 589.9nm.

2)continuous spectra: when a white light frm any source such as sun is analysed

a continious band of colours is obtained.that is called as continuous spectra.

dev_22oct

absorption spectra: when a white light is passed through a tube containing NaCl vapours then the light coming from the other end of the tube when analysed using spectrometer w'll gv u a spectra containing 2 dark line at 589nm and 589.9nm otherwise a continious spectra.....

dev_22oct

dekho jo light NaCl vapours ne absorb ki hai agar aap usko analyse karoge toh aapko emission spectra milega jismein aapko do yellow lines milengi baki ka spectrum dark hoga.

aur jo light absorb nahi hui hai agar aap usko analyse karoge toh aapko do dark lines milengi baki spectrum coloured hoga(all seven colour)

hope it is clear!!

srujana

Pictures to complete the above discussion

catchyash111

Well rated u all!!!!!!

Can u also xplain me wats "series of transition in hydrogen spectrum"????

catchyash111

Well 2 dev_22oct see ur nudgebuk plz!!!!!

srujana

Heres a flash object explaining it

http://www.bigs.de/en/shop/anim/termsch01.swf

(If you can not see the animation, you may not have the plugin player-version by Macromedia"click here" to get it)

catchyash111

Also xplain me wats Plancks Quantum Theory????

catchyash111

plz hlp

dev_22oct

plancks quantum theory:

1)according to that radiation are not continious rather discontinious they exists in the form of packets called quanta or quantum bt specifically in case of light they are called as photons.

2) energy of any radiation is directly proportional to frequency

E

and after removing the sign of proportinality u w'll get a constant called plancks constant h

therefore E=h

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