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我校用物理天平改制了一架电流天平,它除了能定量地测出磁场力 F 外,还能读出电流 I 与磁感应强度 B 间的夹角θ,从而由 I、F、θ来计算出 B 的大小。一、原理与结构我们知道,通电导线在磁场中受磁场力的作用:F=Il×B(适用于长为 l 的通电直导线),磁场力 F 的方向可根据右手螺旋法则或左手定则确定。磁场力的大小 F=IlBsinθ(θ为 I 与 B 的夹角)。将物理天平的左盘取去,改装可转动的磁铁盘和通电线圈,其他结构不变,就制成了电流天平。二、仪器的制作1.绕制线圈:用0.2mm 左右的铜质漆包线绕制一矩形线圈,匝数为50匝,尺寸为30mm×20mm,线
In our school, we used a physical balance to reconstruct a current balance. In addition to measuring the magnetic field force F quantitatively, it can also read the angle θ between the current I and the magnetic induction intensity B, which can be calculated from I, F, and θ. The size of B. First, the principle and structure We know that the power wire in the magnetic field by the magnetic field force: F = Il × B (applicable to the length of the l-powered straight wire), the direction of the magnetic field force F can be based on the right-handed screw rule or left-hand rule determine. The magnitude of the magnetic field force F=IlBsinθ (θ is the angle between I and B). The left side of the physical balance is removed, and the rotatable magnet plate and the energizing coil are modified. The other structures are unchanged and the current balance is made. Second, the production of the instrument 1. Winding coil: a 0.2mm round copper wire around a rectangular coil, the number of turns is 50, the size of 30mm × 20mm, line