Unformatted text preview: alue of b is __________.
(Record your three-digit answer in the numerical-response section on the answer sheet.) 22 Numerical Response
12. The voltage required to stop an alpha particle with an initial speed of
5.34 × 104 m/s is __________ V.
(Record your three-digit answer in the numerical-response section on the answer sheet.) Use the following information to answer the next two questions.
An electron in a hydrogen atom makes a transition from the third energy level
to the ground state.
36. The frequency of light emitted when the electron drops from energy level n = 3 to
n = 1 is
D. 37. 2.2 × 10–8 Hz
1.0 × 107 Hz
5.5 × 1014 Hz
2.9 × 1015 Hz In a hydrogen atom, the ratio of the radius of the third orbital to the radius of the
first orbital is
3:1 The written response questions follow on the next page.
23 Written Response — 15%
1. You have been given a large permanent magnet with a uniform magnetic field
between its poles. In a preliminary experiment, the magnetic field of the permanent
magnet was found to be at least 100 times the strength of Earth’s magnetic field.
Using concepts discussed in the Physics 30 course, design a procedure to measure
the magnitude of the magnetic field. Assume that the space between the poles is
large enough to insert any necessary equipment.
The description of your procedure must include
• a label indicating the direction of the magnetic field between the poles of
the magnet below
• a list of the materials required
• a labelled diagram showing your experimental design
• a description of how to obtain the measurements required to calculate the
magnitude of the magnetic field
• a derivation of the formula used to determine the magnitude of the magnetic field
NOTE: Marks will be awarded for the physics principles used in your response and
for the effective communication of your response. N S 24 Written-response question 2 begins on the next page. 25 Use the following information to answer the next question. In a modified Millikan apparatus, a small, charged object that has a mass of
3.8 × 10–15 kg is suspended by the electric field that is between charged parallel
plates. The table below shows how the balancing voltage depends on the
distance between the plates.
Balancing voltage (103 V)
? Plate separation (mm)
50.0 Written Response — 15%
2. • Provide a graph of the balancing voltage as a function of the plate separation, with
the manipulated variable on the horizontal axis. • Calculate the slope of the graph, and describe the physical quantity or quantities
that this slope represents.
• Using the slope, or another suitable averaging technique, determine the magnitude
of the charge on the suspended mass.
• Determine the balancing voltage required when the plates are separated by 50.0 mm.
Clearly communicate your understanding of the physics principles that you
are using to solve this question. You may communicate this understanding
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- Fall '09
- Physics, Magnetic Field, .........