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在图1所示的示波管中,如果加在电极B上使电子流扫描的电压如图2(α)所示,加在电极A上的电压如图2(b)或(c)所示,在荧光屏上我们将分别看到什么样的曲线? 本题是统编高中下册物理课本第一章中的一个题。这道题包含了丰富的内容,是培养学生思考问题的能力和观察问题的能力的一个好题。但是,有的刊物上刊登的对本题的解答中,没有出现A极、B极的长度及它们的几何中心到荧光屏的距离,得出了圆的方程和X=Y的直线方
In the oscilloscope shown in Fig. 1, if the voltage applied to the electrode B to scan the electron current is as shown in Fig. 2 (α), the voltage applied to the electrode A is shown in Fig. 2 (b) or (c). What kind of curve will we see on the screen? This question is the one in the first chapter of the physics textbook for senior high school students. This question contains a wealth of content. It is a good question for students’ ability to think about problems and to observe problems. However, in some publications, the answers to this question do not show the lengths of the A-pole and B-pole and the distance between their geometric center and the screen, and the equation of the circle and the straight line of X=Y are obtained.