Two scales on a nondigital voltmeter measure voltages up to 20.0 and 30.0 V, respectively. The resistance connected in series with the galvanometer is 1680 Ω for the 20.0-V scale and 2930 Ω for the 30.0-V scale. Determine the coil resistance.

Resistance of the circuit is 820 Ω

Explanation:

Given:

Two galvanometer resistance are given along with its voltages.

Let the resistance is "R" and the values of voltages be 'V' and 'V1' along with 'G' and 'G1'.

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Concept to be used:

Conversion of galvanometer into voltmeter.

Let be the resistance of the galvanometer and the maximum deflection in the galvanometer.

To measure maximum voltage resistance is connected in series .

So,

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We have to find the value of we know that in series circuit current are same.

For                                    For

⇒   equation (i)                ⇒ equation (ii)

Equating both the above equations:

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⇒ Plugging the values.

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The coil resistance of the circuit is 820 Ω .

it becomes positively charged by charging it