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Physics 30

Unit D

Test L. 21-25 Review

1. Consider i.) the cathode ray tube experiment ii.) the gold foil experiment:

a) describe each experiment

b) what was the result

c) what contributions did each make to atomic theory?

d) the cathode ray and gold foil experiments disproved which models of the atom?

2. What was the biggest problem with the Planetary Model of the Atom?

3. Cathode rays are a stream of what type of particle?  What types of fields could potentially deflect cathode rays?

Use the following information to answer the next two questions:

In a cathode ray experiment, it is found that particles travelling at a speed of 7.10 × 106 m/s are deflected by  a 1.06 × 10-4 T magnetic field through a radius of 0.389 m.  

4. What is the charge-to-mass ratio for the particles in this experiment?  (1.72 x 1011 C/kg)

5. It is determined that these particles are singly charged.  What is the mass of these particles?            (9.29 x 10-31 kg)

6. Describe how continuous, emission and absorption spectra may be produced.  Describe the appearance of each spectrum

7. R.A. Dickey was a 'knuckleball' pitcher for the Toronto Blue Jays.  When he threw the ball, it fluttered in the air as it moves towards the batter, making it very hard to hit.  Phil the physics student claims that this fluttering is actually the wave-like characteristics of particles, as suggested by Louis De Broglie.  Is Phil correct?  Explain.

Use the following information to answer the next question:

 

8. Determine the wavelength of one solar-wind electron that has a maximum speed of               4.0 x 105 m/s. 

9. A nucleus with a mass of ‘m’ kg undergoes gamma decay, emitting a photon with a wavelength of λ.  Write a mathematical equation for the recoil speed ‘v’ of the nucleus.

10. Explain what is meant by "Wave-Particle Duality"

Use the following information to answer the next five questions

A Franck-Hertz experiment was done using the fictitious element Rubinium (instead of Mercury).  When Rubinium atoms were bombarded by free electrons, the following energy levels were noted:  5.3 eV, 6.2 eV, 7.6 eV and 11.6 eV.  The ionization level for Rubinium is 12.4 eV.  

11. Create an energy level diagram for Rubinium showing both 0 eV at the ground state and at the ionization level

12. If a free electron with a kinetic energy of 2.2 eV was sent through the Rubinium gas, what would happen?  What about a free electron with a kinetic energy of 10.6 eV?

13. Suppose a Rubinium atom’s electron becomes de-excited from the 11.6 eV level, which drop would result in a photon with the longest wavelength? What would be that wavelength?

14. Suppose Rubinium was a gas in the solar atmosphere.  If a single photon with a wavelength of 1.5 x 10-7 m bombarded an atom of Rubinium, what would happen to the photon?  What kind of spectrum is seen when light from the sun is seen from Earth?

15. When an electron is de-excited from the 11.6 eV energy level, how many possible wavelengths of light are possible?

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16. When an atom's electron undergoes a transition from one stable energy level to another, a photon is emitted with an energy of 2.00 eV .  If the final energy level has an energy of -5.00 eV, determine the energy of the initial level.  

17. When an atom's electron undergoes a transition from one stable energy level to another, a photon is emitted with an energy of 3.00 eV .  If the initial energy level has an energy of 6.00 eV, determine the energy of the final level.