Chapter 30: Quantum Physics
MCAT Study Guide




1.  

The following information pertains to questions 1-4.

A photosensitive surface of a material with work function o is illuminated by a beam of monochromatic light of wavelength o. The light beam has a cross sectional area of 1 mm3 and intensity Io. The rate at which electrons leave the surface is Ro and the most energetic of these electrons have kinetic energy KEo (>1.0 eV).

If the intensity of the illuminating light beam was increased slightly, the kinetic energy of the most energetic electrons leaving the surface would be ___ KEo.

equal to
less than
more than
incomparable with


2.  

If the intensity of the illuminating light beam was increased slightly, the rate at which electrons would be leaving the surface would be ___ Ro.

more than
equal to
less than
incomparable with


3.  

If the wavelength of the illuminating radiation was decreased slightly, the kinetic energy of the most energetic electrons leaving the surface would be ___ KEo.

less than
more than
equal to
incomparable with


4.  

If the work function of the material could be decreased slightly, the kinetic energy of the most energetic electrons leaving the surface would be ___ KEo.

less than
more than
equal to
incomparable with


5.  

The following information pertains to questions 5-9.

In the Bohr model of the hydrogen atom, the allowed energy states are -13.6 eV/n2 and the magnitude of the angular momentum of the electron in its orbit around the proton is n (h/2) where n is the principal quantum number.

If an atom of hydrogen undergoes a transition from the n = 2 state to the n = 3 state, the atom will ___.

absorb 3.4 eV of energy
absorb 1.5 eV of energy
absorb 1.9 eV of energy
emit a 3.4 eV photon
emit a 1.5 eV photon
emit a 1.9 eV photon


6.  

If an atom of hydrogen undergoes a transition from the n = 1 state to the n = 3 state, the atom will ___.

absorb 13.6 eV of energy
absorb 1.5 eV of energy
absorb 12.1 eV of energy
emit a 13.6 eV photon
emit a 1.5 eV photon
emit a 12.1 eV photon


7.  

If an atom of hydrogen undergoes a transition from the n = 3 state to the n = 2 state, the atom will ___.

absorb 3.4 eV of energy
absorb 1.5 eV of energy
absorb 1.9 eV of energy
emit a 3.4 eV photon
emit a 1.5 eV photon
emit a 1.9 eV photon


8.  

If a hydrogen atom undergoes a transition from the n = 1 state to the n = 4 state, the angular momentum of the electron in its orbit will ___ x (h/2).

increase an amount 1
increase an amount 2
increase an amount 3
increase an amount 4
decrease an amount 1
decrease an amount 2


9.  

If a hydrogen atom undergoes a transition from the n = 4 state to the n = 2 state, the angular momentum of the electron in its orbit will ___ x (h/2).

increase an amount 1
increase an amount 2
increase an amount 3
increase an amount 4
decrease an amount 1
decrease an amount 2


10.  

The ionization energy of hydrogen in its ground state is ___ eV.

13.6
6.8
4.5
3.4
1.5
1.2


11.  

Monatomic hydrogen gas is illuminated with "white" radiation. The longest wavelength radiation that will be absorbed by the gas is ___ m.

9.1x10-8
1.0x10-7
1.2x10-7
6.6x10-7
some other value


Bosworth et al, ARCO MCAT SuperCourse (MacMillan, 1997). Copyright 1997, 1996, 1994, 1991 by Stefan Bosworth, Ronald Drucker, Edgar Schnebel, Denise Garlan, Rosie Soy and Marion Brisk. Used by permission of MacMillan, Inc.

For more information, go to http://www.amazon.com.

The Virtual Prof's Physics Study Guide for the MCAT. Copyright 1997 by Glen Terrell and RonJon Publishing, Inc. Used by permission of Glen Terrell. For more information, go to http://www.virtualprof.com.


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