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# Problem: Measuring the EMF and Internal Resistance of a Battery When switch S in the figure is open, the voltmeter V of the battery reads 3.09 V . When the switch is closed, the voltmeter reading drops to 2.97 V , and the ammeter A reads 1.69 A . Assume that the two meters are ideal, so they do not affect the circuita) Find the emf E.Express your answer in volts to three significant digits.b) Find the internal resistance of the batteryc) Find the circuit resistance R.

###### FREE Expert Solution

This problem involves multiple concepts learned in circuits and resistance.

The equation for the terminal voltage is:

$\overline{){\mathbf{V}}{\mathbf{=}}{\mathbf{\epsilon }}{\mathbf{-}}{\mathbf{i}}{\mathbf{r}}}$ where V is the terminal voltage, ε is the emf and r is the internal resistance.

Ohm's law:

$\overline{){\mathbf{V}}{\mathbf{=}}{\mathbf{i}}{\mathbf{R}}}$

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###### Problem Details

Measuring the EMF and Internal Resistance of a Battery

When switch S in the figure is open, the voltmeter V of the battery reads 3.09 V . When the switch is closed, the voltmeter reading drops to 2.97 V , and the ammeter A reads 1.69 A . Assume that the two meters are ideal, so they do not affect the circuit

a) Find the emf E.