Problem & Concept OF Frequency and wave length of emitted radiation (Bohrs atomic model) By-N.K.D. Sir Please -Rate review and share this lesson

Frequency and wave length of emitted radiation Suppose an electronic transition takes place from orbit n2 to n , in hydrogen atom (Z-1) then the emitted energy is where EEnergy of electron in n2 orbit, E," = Energy of electron in n1 orbit (E,-> E,i) 2 -me Now 2 nzh n h 2 -me or

v is the frequency of emitted radiation Now So or where s the wave length of emitted radiation and 1/ ls wave number (wave per centimeter). Hence v wave number -R 22

where R is a constant known as Rydberg constant. For hydrogen like species, the wavelength of emitted radiation is given by the following relation where Z is the atomic numbeir O For an electronic transition between stationary states ni and n2, the value of increases decreases as Z o R- Rydberg constant for hydrogen is 2me 3 Unit of R is cm or meter For Hydrogen the value of R is 109678 cm

The wave number of the first Balmer line of L ion is 1,36,800 cm1 the wave number of the series first line of (in cm') (a)68,400 (c)76,000 Balmer of hydrogen atom IS -1 (b) 15,200 (d) 30,800. Solution: Atomic number of Li'is 3 1,36,800-Rx9 22 3 1 ,36,800 = 1 5,200 22 3

The of Ha line of Balmer series is 6500A. What is the of H line of Balmer series? Solution: For H, lines of Balmer series n 2, n2-3 For H, line of Balmer series n, -2, n, 4 22 3 and By Eqs. (1) and (2) 4 16 80 108 80

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Niranjay Kumar Dwivedi

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Divya K

2 years ago

Thankyou so much sir. The best way to start history preparation is through your crash courses. Gonna start medieval crash course. No one could have done better than you... to complete entire ancient history with the same zeal from start to end within 3 hrs. I am so grateful to you. :)

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