gilvin (jg47854) - 16. Magnetic fields 1 - meyers - (21235) 1
This print-out should have 16 questions.
Multiple-choice questions may continue on 1. toward the left
the next column or page - find all choices
before an
...
gilvin (jg47854) - 16. Magnetic fields 1 - meyers - (21235) 1
This print-out should have 16 questions.
Multiple-choice questions may continue on 1. toward the left
the next column or page - find all choices
before answering. 2. into the page.
001 10.0 points 3. out of the page.
A proton traveling to the right along the xaxis enters a region where there is a mag- 4. toward the top of the page.
netic field of magnitude 1.1 T directed upward
along the y-axis. 5. toward the right
The charge on a proton is 1.60×10−19
If the proton experiences a force of 2.7 ×
10−12 N, find its speed.
Correct answer: 1.53409 × 107
m/s.
Explanation:
Let : B = 1.1 T ,
Fm = 2.7 × 10−12 N , and
qe = 1.60 × 10−19 C .
The magnetic force is
Fm = q v B
v = Fm q B
2.7 × 10−12 N
6. toward the bottom of the page. correct
Explanation:
The force on the electron is
F = q v × B = −e v × B .
The direction of the force is thus
F = −v × B ,
pointing toward the bottom of the page , using right hand rule for v × B , and reversing
the direction due to the negative charge on
the electron.
003 10.0 points
The magnetic field at the equator points
= (1.6 × 10−19 C) (1.1 T) north.
If you throw a positively charged object
= 1.53409 × 107
m/s
002 10.0 points
An electron is in a uniform magnetic field B
that is directed out of the plane of the page, as
shown.
B B
e−
(for example, a baseball with some electrons
removed) to the east, what is the direction of
the magnetic force on the object?
1. Toward the west
2. Upward correct
3. Toward the east
4. Downward
v
Explanation:
Use the right-hand rule: point your index
B B
When the electron is moving in the plane of the
page in the direction indicated by the arrow, the
force on the electron is directed
finger east and your middle finger north. Your
thumb points upward (representing the force on a
positively charged object).
004 (part 1 of 2) 10.0 points
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