Hello everyone, I keep missing his problem! and i only have 2 more trys... When the lights of a car are switched on, an ammeter in series with them reads 14.0 A and a voltmeter connected across them reads 12.0 V (Figure 27-48). When the electric starting motor is turned on, the ammeter reading drops to 12.0 A and the lights dim somewhat. Here is the image: http://www.webassign.net/hrw/hrw7_27-48.gif Fig. 27-48 (a) If the internal resistance of the battery is 0.050 and that of the ammeter is negligible, what is the emf of the battery? wrong check mark V (b) What is the current through the starting motor when the lights are on? A I just thought i could find the EMF of the battery by finding the Potential difference between 2 points i made, a and b, i put a point a right before the resistor and right after the positve pole of the batery i put b. So here is what my equation looks like: Va - RI + E = Vb; now they say somthing about V being 12 V, does that mean Va-Vb = 12? I tried E = RI - 12 = -11.6 which was wrong then i tried to just say screw the Va-Vb and say E = rI E = .7 also wrong! ahh!