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Old Feb 19th 2009, 03:34 AM   #1
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new potential ques(wit attachment)

A gasoline gauge for an automobile is shown schematically in the following illustration. The indicator (on the dashboard) has a resistance of 10 Ω. The tank unit is simply a floar connected to a resistor that has resistance of 140 Ω when the tank is empty, 20 Ω when full, and varies linearly with the volume of gasoline. Find the current in the circuit when the tank is
a. empty
b. half full
c. full
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File Type: bmp quescirc.bmp (949.3 KB, 1 views)
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Old Feb 20th 2009, 06:59 PM   #2
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I guess the chassis is a conductor which completes the circuit

V=IR

a)
12=I (140+10)
I=0.08A

b)let resistance be R
20=140-kV, where k is a proportional constanat and V is the volume
k=120/V
V1=V/2
R=140-(120/V)(V/2)
R=80

12=I(10+80)
I=0.133A

c)
12=I (20+10)
I=12/30
I=0.4A
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