Summary

• Quantized energies
• Bohr atomic model

• Quantum mechanics
  • Particles and waves
  • The wave function Ψ
  • wavepackets applet
  • two-slit experiment applet
    Example #1
    
    Example #2
    
  
  
  
• Uncertainty principle
  • momentum & position
    Example #3
    
  • wavepacket propagation
  • energy & time
    Example #4
    
  • electrons in a box
  
  
  

klm
If you wish to expand the two-slit interference bands created by electrons, you should _____ the accelerating voltage ΔV.
A. increase                     B. decrease
C. It makes no difference.
Answer







sj6 41.2
Through what ΔV are electrons accelerated so that interference bands 0.4 mm apart appear on a screen 20 cm from two slits 0.06 µm apart?
A. 35.5 mV               B. 11.7 V
C. 105 V                   D. 25.0 kV
Answer







kw5
An electron passes through a 1×10^-10 m wide slit. What uncertainty Δv does this introduce in the velocity of the electron at right angles to the slit?
A. 3.00×10⁸ m/s
B. 1.16×10⁶ m/s
C. 6.85×10^-8 m/s
D. 1.05×10^-24 m/s
Answer







gc6 28.5
An electron remains in an excited state of an atom for 1×10^-8 s. What is the minimum uncertainty in the energy of the state?
A. 1.05 eV                  B. 15.2 meV
C. 87.6 µeV                D. 65.9 neV
Answer







 



B. decrease
Decreasing the electron speed will increase its wavelength and therefore create a wider interference pattern.












 



C. 105 V













 



B. 1.16×10⁶ m/s














 



D. 65.9 neV