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Question: Answered & Verified by Expert
An electron is in an excited state in a hydrogen like atom. It has a total energy of -3.4 eV . The kinetic energy is E and its de Broglie wavelength is λ . Then
PhysicsAtomic PhysicsNEET
Options:
  • A E = 6.8 eV,  λ = 6.6 × 1 0 - 1 0 m
  • B E = 3.4 eV,  λ = 6.6 × 1 0 - 1 0 m
  • C E = 3.4 eV,  λ = 6.6 × 1 0 - 1 1 m
  • D E = 6.8 eV,  λ = 6.6 × 1 0 - 1 1 m
Solution:
1768 Upvotes Verified Answer
The correct answer is: E = 3.4 eV,  λ = 6.6 × 1 0 - 1 0 m
K.E.= KZ e 2 2r

P.E.= KZ e 2 r

T.E.=P.E.+K.E.= KZ e 2 2R

Therefore, TE=KE= PE 2 =3.4 eV

So, KE=3.14 eV

Let p = momentum and m = mass of the electron.

E= p 2 2m or p= 2mE

de Broglie wavelength,

λ= h p = h 2mE

On substituting the values, we get

λ= 6.63× 10 34 2×9.1× 10 31 ×3.4×1.6× 10 19

=6.6× 10 10 m

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