A circuit is arranged by connecting a resistor of resistance $R$ across the terminals of a battery with electromotive force (e.m.f.) $9.0\,\text{V}$ and a constant internal resistance $r$. A charge of $6.0\,\text{C}$ passes through the resistor in a time of $2.0\,\text{minutes}$, producing $48\,\text{J}$ of thermal energy dissipation. What is the internal resistance $r$ of the battery?
- A$0.17\,\Omega$
- B$0.33\,\Omega$
- C$20\,\Omega$
- D$160\,\Omega$