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初三物理“导体和绝缘体”一节中说:“取两个相同的验电器A、B,使A带电,B不带电(见初中物理第二册124页图甲),拿一根带橡胶柄的金属棒,把这两个验电器连接起来,可以看到,B的金属箔张开了,同时,A的金属箔张开的角度减小了(见初三物理第二册124页图乙),这表示A上的一部分电荷通过金属棒传到B上去了。” 我认为这段话,表述不够周严,理由如下:使验电器A带电,B不带电,用金属棒连接验电器A、B后,电荷是从A传到B,还是从B传到A,这要看验电器A带的是什么电荷。若验电器A带负电,
In the third year of the physical “Conductors and Insulators” section, we said: “Take two identical electroscopes A and B to make A electrified and B to have no electrification (see junior high school physics volume 2 on page 124, figure A) and take a piece of rubber. The metal rod of the handle connects the two electroscopes and it can be seen that the metal foil of the B is opened, and at the same time, the angle of opening of the metal foil of A is reduced (see the physical diagram of the third volume on page 124). B) This means that a part of the charge on A was transferred to B by a metal rod.” I think that the description is not strict enough. The reasons are as follows: to make the electroscope A charged, B not charged, and to connect the electroscope with a metal rod After A, B, the charge is transmitted from A to B, or from B to A, which depends on what charge A is carrying. If electroscope A is negatively charged,