Current location - Training Enrollment Network - Mathematics courses - The title is "Where is Xiao Ming's mistake?" It is the second model of physics in the senior high school entrance examination in Hongkou District (20 12).
The title is "Where is Xiao Ming's mistake?" It is the second model of physics in the senior high school entrance examination in Hongkou District (20 12).
First, draw two circuit diagrams, one is the correct connection (Figure A) and the other is the voltmeter measuring sliding rheostat (Figure B).

The small lamp voltage in Figure A is 3.5 volts, while the sliding rheostat voltage in Figure B is 3.5 volts.

Because "the slider of the rheostat in Xiaohua circuit is near the midpoint position", the resistance of the sliding rheostat at this time is about 10 ohm or 25 ohm.

Multiply the ammeter of 0.24 amp by 10 ohm or 25 ohm respectively, and the voltage of the sliding rheostat is about 2.4 volts or 6 volts, which is not consistent with Figure B.

So picture A is a small flower and picture B is Xiao Ming.