In the circuit shown, $R_1=R_2=R_3=R_4=R_5=13\mathrm{.}0.$

A voltmeter measures the potential difference across the battery.

When the switch is in position $1,$ the voltmeter measures $V_1=13\mathrm{.}1V.$ When the switch is in position $2,$ the voltmeter measures $V_2=12\mathrm{.}2V.$

What is the emf $$ of the battery?

$=$

$$

v

What is the battery's internal resistance $r?$

$r=$

$$

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