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kaspis245
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Homework Statement
A circuit contains 9V battery ,which internal resistance is unknown, an ammeter and a voltmeter, whose resistances are also unknown. When a resistor was connected to the voltmeter in parallel, the voltmeter's value was reduced 2 times and the ammeter's value doubled. What did the voltmeter show before the resistor was connected?
Homework Equations
Kirchhoff's Rules
The Attempt at a Solution
Here's my drawing:
I know that:
##I_2=2I_1##
##V_1=2V_2##
From first drawing I get:
##V_1=I(r_1+r)##
##I_1=I-9/r##
If I could express the same values (V1 and I1) maybe I could equate them and get the answer, but I am not sure how to do this.