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比较灯泡亮度的问题是中考中的常见题,为了帮助同学们提高分析判断能力,现举例分析如下。1 在并联电路中 例1 灯泡L_1标有“220V 25W”,L_2标有“220V 60W”,将它们并联接在220V的电路中,哪灯较亮? 分析:两灯并联时,实际电压都达到了各自的额定电压,实际功率也都达到了各自的额定功率,所以L_2比L_1亮。 例2 将例1中的两个灯泡并联接在180V的电路中,哪灯较亮?
The problem of comparing the brightness of light bulbs is a common problem in the examinations. To help students improve their analytical abilities, examples are as follows. 1 In the parallel circuit example 1 bulb L_1 is marked with “220V 25W” and L_2 is marked with “220V 60W”, and they are connected in the circuit of 220V, which lamp is brighter? Analysis: When two lamps are connected in parallel, the actual voltage reaches With their respective rated voltages, the actual power also reaches their respective rated power, so L_2 is brighter than L_1. Example 2 Which of the two light bulbs in Example 1 are connected in a 180V circuit and which light is brighter?