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所谓线框转动切割,通常是指线框绕莱一固定轴在磁场中转动而切割磁力线。由于这类电磁感应难度较大,且问题涉及的知识点多,信息量大,综合性强。因此已成为高考命题中的热点内容。本文试就线框在匀强磁插,直线电流磁场,辐向磁场中转动切割的考题为例。给予分类解析与评述。 一、线框在匀强磁场中转动切割 例1.如图1所示,单匝闭合的线框在匀强磁场中以角速度ω绕中心轴OO＇逆时针匀速转动。已知线框的边长ab=cd=L_1=0.20米,bc=ad=L_2=0.10米,线框的电阻值R=0.50欧姆,角速度ω=300弧度/秒。匀强磁场磁感应强度的大小为B=0.50特斯拉,方向与转轴OO＇垂直,规定当线框平面与B垂直并且ab边在纸面前时,开始计算线框的转角θ。
The so-called wire frame rotary cutting, usually refers to the wire frame around Lai a fixed axis in the magnetic field rotation and cutting magnetic lines. Due to the difficulty of such electromagnetic induction, and the problems involved in many issues, a large amount of information, comprehensive and strong. Therefore, it has become a hot topic in the college entrance examination proposition. In this paper, we will try the example of the wireframe in the uniform magnetic insertion, linear current magnetic field, and radial magnetic field cutting examination. Give classification analysis and review. First, the wire frame is rotated in a uniform magnetic field. Example 1. As shown in Fig. 1, the single-turn closed wire frame rotates at a uniform speed counterclockwise around the central axis OO′ in a uniform magnetic field at an angular velocity ω. The side length of the wire frame is known as ab=cd=L_1=0.20 meters, bc=ad=L2=0.10 meters, the resistance value of the wire frame is R=0.50 ohms, and the angular velocity is ω=300 rad/sec. The magnetic field intensity of the uniform magnetic field is B=0.50 Tesla, and the direction is perpendicular to the axis OO′. It is specified that when the plane of the wireframe is perpendicular to B and the ab side is in front of the paper, the angle θ of the wireframe begins to be calculated.