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(a) State Bohr's postulateto define stableorbits in hydrogenatom. Howdoes de Broglie'shypothesis explainthe stability of these orbits ?(b) A hydrogen atom initially in the groundstate absorbs a photon whichexcites itto then n = 4 level . Estimate the frequenyof the photon. |
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Answer» Solution :Bohr. s postulate for stable orbits ,states The electron , in an atom revolves around the mucleus only in those orbits for which its angular MOMENTUM is an intergal multiple of` (h)/( 2h ) (h= `planck. s constant ) [Also accept mvr=`n.( h)/(2PI ) (n=1,2,3......) ` As per de Brogle.s hyothesis ` lambda =(h)/(p) =(h)/( mv) ` For a stable orbit we, must have circumference of the orbit `=n( n=1,2,3..........) ` ` therefore 2pi r =n.mv` or `mvr =(nh)/( 2pi) ` Thus de- Broglie showed that formation of stationary PATTERN for integral .n. gives RISE to stability of the atom . This is nothing but the Bohr.s postulate |
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