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Wave Optics

Question
CBSEENPH12039883

Hydrogen atom in ground state is excited by a monochromatic radiation of straight lambda space equals space 975 space straight A with straight o on top. The number of spectral lines in the resulting spectrum emitted will be,

  • 3

  • 2

  • 6

  • 10

Solution

B.

2

Energy provided to the ground state electron,
equals space hc over straight lambda space

equals space fraction numerator 6.6 space straight x space 10 to the power of negative 34 end exponent space straight x space 3 space straight x space 10 to the power of 8 over denominator 975 space straight x space 10 to the power of negative 10 end exponent end fraction

equals space fraction numerator 6.6 space straight x space 3 over denominator 975 end fraction straight x 10 to the power of negative 16 end exponent

equals space 0.020 space straight x space 10 to the power of negative 16 end exponent

equals space 2 space straight x space 10 to the power of negative 18 end exponent space straight J

equals space fraction numerator 20 space straight x space 10 to the power of negative 19 end exponent over denominator 1.6 space straight x space 10 to the power of negative 19 end exponent end fraction space eV

equals space fraction numerator 20 over denominator 1.6 end fraction space eV

equals space 12.5 space eV
The electron will jump from n= 3 to n=1.
The number of possible field lines from n=3 to n=1 is 2.