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Homework Statement
A galvanometer of coil resistance 50.0 Ω deflects full scale for a current of 3.50 mA. What series resistance should be used with this galvanometer to construct a voltmeter which deflects full scale for 35.0 V
Homework Equations
/Known Variables[/B]R1 + R2... + Rn = Rtotal
R = V/I
Vv = 35V; Rg = 50 Ω; I = 3.50 mA or 0.0035 A
The Attempt at a Solution
Since a voltmeter occurs in a series, I have used the relevant equation above (Rv + Rg = Rtotal) where Rtotal = Vv/I (since current is constant). Replacing Rtotal with Vv/I gives Rv + Rg = Vv/I, so to find the resistance of the voltmeter, it would be Rv = (Vv/I) - Rg. Substituting the values in gives (35/0.0035) - 50 so Rv = 9,950 Ω (9.95 x 10^3 Ω). This means that Rtotal = 10,000 Ω (1.00 x 10^4 Ω).
Help and feedback is very much appreciated!
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