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Unformatted text preview: 0 × 10–14 Hz C. 1.6 × 1019 Hz D. 3.2 × 1019 Hz 15 Use the following information to answer the next three questions.
An Application of the Photoelectric Effect
On movie film, the sound track is located along the side of the film strip and
consists of light and dark regions. Light from the projector is directed
through the sound track and onto a phototube. Variations in the transparency
of the regions on the sound track allow varying intensities of light to reach the
(side view) Phototube Light source I Amplifier II Speaker III
15 Film strip
(front view) IV Sound track 26. The region of the sound track that will allow the most electrical current to be
produced in the phototube is labelled
IV 16 27. The energy that is required to remove the electron from the photoelectric surface in
the phototube is called the
D. work function
electric potential energy
maximum kinetic energy Numerical Response
7. In one second, 1.45 × 1016 photons are incident on the phototube. If each of the
photons has a frequency greater than the threshold frequency, then the maximum
current to the amplifier, expressed in scientific notation, is a.bc × 10–d A. The
values of a, b, c, and d are _____ , _____ , _____ , and _____ .
(Record your four-digit answer in the numerical-response section on the answer sheet.) Use the following information to answer the next question.
Electron microscopes use the wave nature of electrons to detect objects that
are too small to see with visible light. In order to detect an object, the
wavelength used must be the same size or smaller than the object.
The momentum of a particle is related to its wavelength by the formula p = λ .
Important medical breakthroughs have resulted from viewing viruses that are
5.00 × 10–9 m in diameter. Numerical Response
8. In order for a virus to be detected by an electron microscope, the minimum speed
that the electrons must have in the electron microscope, expressed in scientific
notation, is b × 10w m/s. The value of b is __________.
(Record your three-digit answer in the numerical-response section on the answer sheet.) 17 Numerical Response
9. For a 768 g sample of an unknown radioactive element, 48.0 g remain after
10.2 h. The half-life of the element is __________ h.
(Record your three-digit answer in the numerical-response section on the answer sheet.) Use the following information to answer the next two questions.
In medical diagnosis, a patient may be injected with a radioactive isotope.
As the isotope decays, the gamma ray emissions are detected and a computer
builds images of the patient’s blood flow and organs.
A radioactive isotope commonly used in medical diagnosis is technetium-99.
This isotope has a half-life of 6.00 h and decays to a stable isotope by
gamma ray emission. 28. If the biological processes that might eliminate some of the technetium-99 from the
body are ignored, the maximum percentage of radioactive technetium-99 that could
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- Fall '09