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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 of the electron is E and its de Broglie wavelength is λ
PhysicsAtomic PhysicsNEET
Options:
  • A E=6.8 eV,  λ~6.6×10-10 m
  • B E=3.4 eV,  λ~6.6×10-10 m
  • C E=3.4 eV,  λ~6.6×10-11 m
  • D E=6.8 eV, λ~6.6×10-11 m
Solution:
2675 Upvotes Verified Answer
The correct answer is: E=3.4 eV,  λ~6.6×10-10 m
PE=-2 KE=-2E

Total Energy PE+KE=-2E+E =-E

-E= -3.4 eV

or E=3.4 eV

Let p is momentum and m is mass of the electron

E=p22m

or p= (2mE) .

de Broglie wavelength λ=hp=h(2mE) 

λ=6.6 x 10-10 m

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