(do not write on formula sheets)
iron atoms emit green light of wavelength 527 nm. Calculate the energy of these photons
and compare the value with that of photons from BBC radio of wavelength
is the deBroglie wavelength of an electron, m =
9.1 x 10-31 kg, and a velocity , v = 3
x 105 m/s.?
the order in which orbitals are filled, determine the electron
configuration of Iodine (Z = 53).
bond energies of the diatomic molecules O2 and N2
are 4.93 x 108 J/k mol and 9.40x108
J/k mol respectively. What is meant
by bond energy, and what are the reasons for the difference in these
values? Calculate the energy, in eV, required to separate each molecule into its
constituent atoms. The Hydrogen
bond between water molecules has energy 5.00 x 107
J/k mol. Give reasons for
its low value compared with those above.
What frequency of radiation is required to dissociate two water
concentration of an element in a sample may be determined by X-Ray
fluorescence, where atoms are excited by X-Rays and emit characteristic
X-Rays which are detected and counted.
Copper atoms emit such fluorescent X-Rays of wavelength 0.154
nm. What is the minimum tube
voltage required to excite this fluorescence?
sample of 128I53 contains 2.0 x 1010
radioactive nuclei. (a) If the half-life of this isotope is 25 minutes,
calculate the decay constant. (b)
How many nuclei are still radioactive after 24 hours?
standard source containing 2.0 mCi
of tritium is monitored by a liquid scintillation counter and 120 cps are
recorded. Calculate the activity of a sample
which gives a count rate of 270 cps.
dating is based on the assumption that the ratio of C-14 to stable C-12
atoms in the atmosphere has remained constant for thousands of years, and
that all living organisms contain this prescribed ratio of carbon
atoms. Upon death, C-14
incorporation ceases and the amount then present decays at the
characteristic rate with a half life of 5580 years. Therefore the determination of the
specific activity of carbon fixes the time of death. The specific activity of a sample of
carbon from a wood relic is 4.5 nCi/kg. If the specific activity of a sample of
old wood is 0.28125 nCi/kg today, how old is the
sample of wood?
- In the
Bohr model of the atom, an electron making transitions from a higher energy
state to a lower energy state produces discrete line spectrum. When the
electron makes a transition from a state with an energy of - 0.544 ev to a state having an
energy of - 3.40 ev. What is the
wavelength of the photon emitted?
that the energy level for a certain element is given by En = . What is the
frequency of a photon emitted from a transition from a
n=4 to an n=2 state?
11. The Pauli
Exclusion Principle states
a. No two
electrons can have the same set of quantum numbers.
b) There is
an inherent uncertainty in the position and momentum of a particle
c) When an
atom has orbitals of equal energy, the maximum number of electrons will have
d) when an electron is in a stationary orbit it will not radiate
12. Find the
binding energy (in Mev) of carbon-12.
Assume: mC =
11.996706 u mp = 1.007276 u mn
= 1.008665 u
13. Radioactive polonium, decays by alpha
a. b. c. d. e.
14. The same spectroscope is used to obtain the five spectra
in the figure below: What elements can
you identify in sample (a) and in sample (b)?
15. . Determine the energy, Q value, for the reaction
: 2713Al + 10n
2411Na + 42He
He 4.002603 Al 26.981541 Na 23.990964 n 1.008665
16. . Deuterons that have been
accelerated to a high velocity have been used to bombard other deuterium
nuclei, resulting in the reaction:
+ 21H ® 32He + 10n What is the Q value for this
21H = 2.014102 32He = 3.016029 10n =
17. The function of the “control rods” in a nuclear reactor
a)increase fission by slowing down
b)decrease the energy of the
neutrons without absorbing them
c) decrease fission by absorbing
d) increase the ability of the
neutrons to cause fission
e) provide the critical mass for
the fission reaction
18. The purpose of a “moderator” in a nuclear reactor is
neutrons for the fission process
- react with the uranium to release energy
down fast neutrons to increase the probability of fission
the dangerous gamma radiation
the reactor operator from dangerous radiation
19. For a controlled nuclear fusion reaction, one needs:
density n and high temperature T
- high n
and low T
- low n
and high T
n and low T
- high n
and T = 0 °K
20. A spaceship is measured to be 120
m long while it is at rest with respect to an observer. If this spaceship now flies past the observer
with a speed of 0.99 c,
what length will the observer measure for the length of the
21. Describe the difference between Nuclear fission and Nuclear Fusion.