Light of wavelength 1281.8nm is emitted when an electron of hydrogen atom drops from 5th to 3rd energy level calculate the wavelength of the photon emitted when electron falls from 3rd to ground level. 

Asked by Taniyarana150 | 23rd May, 2019, 12:01: AM

Expert Answer:

Energy change in emission is calculated by-
C a s e minus left parenthesis 1 right parenthesis
increment E equals fraction numerator h C over denominator lambda end fraction
space space space space space space equals negative R left parenthesis 1 over n subscript 2 squared minus 1 over n subscript 1 squared right parenthesis
space space space space space fraction numerator R over denominator C h end fraction space space equals fraction numerator negative left parenthesis begin display style 1 over n subscript 2 squared end style minus 1 over n subscript 1 squared right parenthesis over denominator lambda end fraction
space space space space space space space space space space space space space space equals fraction numerator negative left parenthesis 1 over 3 squared minus 1 over 5 squared right parenthesis over denominator 12818 cross times 10 to the power of negative 9 end exponent end fraction space space space space space space space space space space space space left parenthesis 1 m equals 10 to the power of negative 9 end exponent m right parenthesis

C a s e minus left parenthesis 2 right parenthesis
1 over lambda equals negative fraction numerator R over denominator C h end fraction left parenthesis 1 over n subscript 2 squared minus 1 over n subscript 1 squared right parenthesis
1 over lambda equals negative fraction numerator negative left parenthesis 1 over 3 squared minus 1 over 5 squared right parenthesis over denominator 12818 cross times 10 to the power of negative 9 end exponent end fraction left parenthesis space 1 over 2 squared space minus 1 over 3 squared space right parenthesis

space space space space space lambda space space equals space space 129782.25 space cross times 10 to the power of negative 9 end exponent space m

Answered by Ravi | 23rd May, 2019, 12:50: PM