A standard D cell flashlight battery is connected to a load of 3 ohms. After 6 hr of intermittent use the load voltage drops from an initial 1.5 V to a final useful voltage of 0.9 V.
(a) Calculate the internal resistance of the battery at the load voltage of 0.9 V.
(b) Calculate the average value of voltage V during the useful life of the battery.
(c) Calculate the average value of current I during the useful life of the battery.