Pre-Lab: Magnetic Fields Name:

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18 Οκτ 2013 (πριν από 3 χρόνια και 10 μήνες)

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Phy 133L

CSU Pomona

11/08/12

Dr. Julie J. Nazareth

Pre
-
Lab
: Magnetic Fields





Name:

=====================================================================

Multiple choice. Choose the
best

answer.





(10 points possible)


1. What is the source of a magnetic field?

[1 pt]

a. changing voltage

b. curren
t

c. resistance in a wire


d. None of these.


2. According to the lab manual, what method(s) can be used to calculate magnetic fields?


a. Ampere’s law



c. Oersted’s law


e. Answers a and b


[1 pt]

b. Faraday’s law


d. Biot Savart law


f. Answers

a and d


3. When can equation 2 in your lab manual be used?


[1 pt]

a. for an infinitely long solenoid

b. for a finite solenoid

c. when the length of the coil is small compared to the coil’s radius

d. when the length of the coil is large compared to
the coil’s radius


4. What is the magnetic field outside an infinitely long solenoid?


[1 pt]

a.
µ
0
ni

b. nearly zero except close to the ends

c. 0


d. very large


5. In this lab experiment, how will we measure the strength of the magnetic field?


[1
pt]

a. find the amplitude of the voltage induced in a search coil

b. find the amplitude of the current induced in a search coil using Faraday’s law

c. use a magnetic field detector


6. If the lab apparatus on your lab bench is set
-
up backwards relative

to figure 1, how do you
know the search coil is centered in the solenoid?


[1 pt]

a. the 100 cm mark on the meter stick is flush with the left side of the tube

b. the 0 cm mark on the meter stick is flush with the end of the tube near the large coil

c.

the 0 cm mark on the meter stick is flush with the end of the tube near the solenoid

d. the amplitude on the oscilloscope is at a minimum


7. According to the lab manual, what frequency should you set the function generator to?

a. 70%


b. 12.0 kHz


c
. 68 kHz


d. 1000Hz


[1 pt]


8. According to the lab manual, where do you find the scaling factor?

[1 pt]

a. lower right of screen


c. lower left of screen

b. upper right of screen


d. upper left of screen


9. Solenoid graph of log voltage versus l
og distance: According to the lab manual, “At either
end of your graph, the curve should approach a straight line.” What should the slopes of
these straight line segments be theoretically equal to?


[1 pt]

a. 1, 1


b.
-
3,
-
3/2


c.
-
3,
-
3


d. 0,
-
3/2


e. 0,
-
3


10. Large coil graph #2 (log voltage versus log (R
2

+ x
2
): According to the lab manual, what
should the slope of the best fit line to your data be equal to?


[1 pt]

a. 0

b.
-
3


c.
-
3/2


d. 3


e. 3/2