Q 2) i have a 12v DC automobile head lamp rated 50W a resistor is to be connected in series with the lamp to permit to operate on 24v. what is the resistor and power rating. i did mind like R=E^2/R R=12^2/50=2.88R. then power rating on the resistor is 50W. im i on the right track Q 2) a circuit contains 8 incandescent lamps connected in series across 480 volt and one is defective and you got find which one. Meters available are voltmeter, ohmmeter and ammeter. which meter would you use in shortest time determine defective lamp, how'd s it and why i'd use ammeter cause got a low resistor and must be connected across circuit with load to limit flow of current. is that correct? i'm kinda not really sure--second opinion.