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leena19
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Homework Statement
A millivoltmeter of resistance 5[tex]\Omega[/tex] gives fullscale deflection,when connected across 75mV.
Inorder to use this millivoltmeter as an ammeter,a resistance coil with a third terminal C,is connected between terminals A and B ,of the millivoltmeter.
When a current of 1.5A is flowing between A and C,and a current of 0.15A flows between A and B,the instrument shows full scale deflection.
Find the resistances of the 2 portions AC and BC
Answers given are :AC=1/18 ohms
BC =0.5 ohms
Homework Equations
Kirchoffs' laws
[tex]\sum[/tex]E = [tex]\sum[/tex]IR
The Attempt at a Solution
I managed to draw a diagram of the circuit(I hope it's correct?),but now, I'm having trouble trying to determine the currents(I and I-i,as labelled in the diagram).
Using,
V=IR for the millivoltmeter
75*10^-3 = i * 5
I get i= 15mA ,which, I think ,has to be the current flowing through the milivoltmeter inorder to obtain a fullscale deflection,but,
what is I? Is it 1.5A+0.15A?
Thank you