论文部分内容阅读
在编制物理习题时,一个知识点可以编制出几个,甚至几十个题目.在物理教学中,如果真正突破一个难点,往往能使学生解决一大类物理习题.下面以“恒定电流”为例作具体讨论. 一、找出知识难点部编教材高中物理下册中有这么两个题目:在图1所示的分压器电路中接入一个伏特表测U_(PB)的值,在P从A向B滑动的过程中,如果伏特表的示数始终等于U,故障出在哪里?(第64页) 在图2所示的电路中,L_1、L_2都标“220伏”的灯泡,电键K闭合时V_1、V_2、A的读数分别为220伏、110伏、0.2安.F是熔断电流为0.35安的保险丝.在下列情况下可能是哪个灯发生了什么毛病: ①两灯不亮,V_1和V_2的读数都是220伏,A的读数为零; ②两灯不亮,V_1的读数是220伏,V_2、A的读数为零: ③保险丝熔断.(第69页) 这类问题学生普遍
In the preparation of physical exercises, a knowledge point can be prepared to several, even dozens of topics. In the physics teaching, if you really break a difficult point, students can often solve a large class of physical problems. The following “constant current” is Examples for specific discussion. First, to find out the difficulties of the Department of Teaching Materials for the Department of Physics There are two topics in the high school physics book: In the voltage divider circuit shown in Figure 1, a voltmeter is connected to measure the U_(PB) value. When P slides from A to B, if the indication of the voltmeter is always equal to U, where is the fault? (p. 64) In the circuit shown in Figure 2, L_1 and L_2 are all marked “220 volt” bulbs. When the key K is closed, the readings of V_1, V_2, and A are 220 volts, 110 volts, and 0.2 amps, respectively. F is a fuse with a fuse current of 0.35 amps. Which of the lamp’s faults may occur in the following cases: 1 On, V_1 and V_2 both read 220 volts and A reads zero; 2 both lights are off, V_1 reads 220 volts, V_2, A reads zero: 3 fuse blows (page 69) Students are generally problematic