p41_066 - 66. (a) We denote the upper level as level 1 and...

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66. (a) We denote the upper level as level 1 and the lower one as level 2. From N 1 /N 2 = e ( E 1 E 2 ) /kT we get (using the result of problem 3 in Chapter 39) N 1 = N 2 e ( E 1 E 2 ) /kT = N 2 e hc/λkT =( 4 . 0 × 10 20 ) e (1240 eV · nm) / [(580 nm)(8 . 62 × 10 5 eV / K)(300 K)] =5 . 0 × 10 16 ¿ 1 , so practically no electron occupies the upper level. (b) With N 1 =3 . 0 × 10 20 atoms emitting photons and
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This note was uploaded on 11/12/2011 for the course PHYS 2001 taught by Professor Sprunger during the Fall '08 term at LSU.

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