Analysis of test questions: As can be seen from the observation figure 1-2, when the object is weighed, the slider P of the sliding rheostat R will slide to the B end, and the length of the resistance wire connected to the circuit becomes smaller, and the resistance of the conductor is directly proportional to its length. The resistance of the rheostat connected to the circuit becomes smaller, the total resistance (R+R') in the circuit becomes smaller, and the voltage remains unchanged. According to ohm's law, the current in the circuit becomes larger, which is the ammeter. I 2, then g1< G2.