Download Pre-Lab: Electric Fields

Phy 123L/133L
Pre-Lab: Analog Galvanometer
Name:
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Choose the best answer.
(10 points total)
A galvanometer can be used as an ammeter or a voltmeter by combining it with an external
resistor in a specific way.
In the lab manual, Ig and r are called the galvanometer characteristics.
1. Which variable does the lab manual use to denote the internal resistance of the galvanometer
coil?
a. r
b. Ig
c. M
d. V
e. s
f. R
2. Which variable does the lab manual to represent the current needed to cause a full scale
deflection of the pointer?
a. r
b. Ig
c. M
d. V
e. s
f. R
3. To use the galvanometer as a voltmeter, the external resistance is added where?
a. In series with the part being measured
c. In series with the galvanometer
b. In parallel with the part being measured
d. In parallel with the galvanometer
4. To use the galvanometer as an ammeter, the external resistance is added where?
a. In series with the part being measured
c. In series with the galvanometer
b. In parallel with the part being measured
d. In parallel with the galvanometer
5. For a voltmeter, the resistance combined with the galvanometer should be
a. High
b. Low
c. None should be added
6. For an ammeter, the resistance combined with the galvanometer should be
a. High
b. Low
c. None should be added
7. An ammeter measures the _____ flowing through a circuit and therefore, must be placed in
the circuit.
a. resistance
b. current
c. voltage
d. power
8. A voltmeter measures the _____ between two points in a circuit and therefore, must be placed
across a part of the circuit.
a. resistance
b. current
c. voltage
d. power
9. In part 3, Ammeter, where do you connect your leads to your galvanometer?
a. plug into the binding posts/terminals
b. connect alligator clips to the straight ends of the wire shunt
10. In the lab, to turn your galvanometer into an ammeter, you will construct a shunt resistor out
of copper wire that has a resistance of 0.000530 Ohms/cm. If you want a shunt resistance of
0.0105 Ohms, how long should your wire shunt be?
a. 19.8 cm
b. 0.0505 cm
c. 5.56x10-6 cm
CSU Pomona
OK Fall 2012
Dr. Julie J. Nazareth