You find an old battery with an unknown EMF, \varepsilonε, and an unknown internal resistance, r. You can characterize the battery using two known resistors and a good ammeter. When you put the battery in series with the first resistor R_1 = 100~\OmegaR 1 =100 Ω, you measure a current through it of I_1 = 0.093 AI 1 =0.093A. You then remove the first resistor and replace it with the second resistor, R_2 = 500~\OmegaR 2 =500 Ω, and now measure a current through it of I_2 = 0.019I 2 =0.019. Calculate the internal resistance of this mystery battery. Assume the ammeter is ideal and has negligible resistance)