Internal Resistance of a Battery Lab Report Example | Topics and Well Written Essays - 250 words

Internal Resistance of a Battery - Lab Report Example The rheostat’s resistance is then varied a number of times, taking the current and voltage readings for each turn. The equation V = ÃŽ µ - Ir, is then used to determine the internal resistance of the battery, where V is the recorded total voltage drop across the battery, ÃŽ µ, the electromotive force or the total voltage put out by the battery, I the current flowing through the circuit and r the required internal resistance of the household battery. ÃŽ µ, V, and I, are measured and then the equation V = ÃŽ µ – Ir used to determine r which is then compared to accepted values. A possible limitation to this experiment that may lead to inaccurate results is the resistance of the connecting wires that is never taken to account. A new 9-volt battery was obtained and the voltage it could put out measured and recorded. Next, the slide on the rheostat was put to the extreme right—its maximum level--and its resistance measured and recorded. The circuit was then connected as shown in figure two below, keeping the switch open and taping its base to the table for stability (Internal Resistance of a Battery, p 2). The high current (20A) input of the ammeter was used, setting it up to the appropriate scale. Everything was now set for measurement taking. In quick moves, the switch was closed, both the voltage and current readings recorded and then the switch opened immediately. A few seconds were then to pass before the next measurements were taken (Internal Resistance of a Battery, p 2). The rheostat was the disconnected and its resistance decreased by sliding it a few centimetres to the left. This resistance was then measured and recorded. The circuit was then reconnected and the above procedure of taking measurements repeated. Next, the rheostat was disconnected and moved a few more centimetres to the left. As in the previous steps, the resistance was measured and recorded, the circuit reconnected and the current and voltage measurements repeated as