Structure of Atom

Structure of Atom

Question

Energy of an electron is given by
E =- 2.178 x 10-18open parentheses straight Z squared over straight n squared close parentheses
Wavelength of light required to excite an electron in a hydrogen atom from level n =1 to n=2 will be (h=6.62 x 1034 Js and c = 3.0 x 108 ms-1

  • 1.214 x 10-7 m

  • 2.816 x 10-7 m

  • 6.500 x 10-7 m

  • 8.500 x 10-7

Answer

A.

1.214 x 10-7 m

increment straight E space equals space 2.178 space straight x space 10 to the power of negative 18 end exponent space open parentheses 1 over 1 squared minus 1 over 2 squared close parentheses space equals space hc over straight lambda
2.178 space straight x space 10 to the power of negative 18 end exponent space open parentheses 1 over 1 squared minus 1 over 2 squared close parentheses space equals fraction numerator 6.62 space straight x space 10 to the power of negative 34 end exponent space straight x 3.0 space straight x space 10 to the power of 8 over denominator straight lambda end fraction
straight lambda space equals space 1.21 space straight x space 10 to the power of negative 7 end exponent space straight m

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