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题目:一电热器有两根电阻丝,当只给一根通电时,需要 t_1秒钟才能煮沸一壶水;当只给另一根通电时,需要 t_2秒钟才能煮沸一壶水。若将两根电阻丝并联起来使用,则煮沸一壶水需要多少时间?分析:两根电阻丝单独使用或并联起来使用,由于均接在同一电源上(设电源电压为u),每段电阻丝两端的电压不变,所以各自的工作状态不变。设:一根电阻丝的电阻为 R_1,通
Title: An electric heater has two resistance wires. When only one power is applied, it takes t_1 seconds to boil a pot of water. When the other is powered only, it takes t_2 seconds to boil a pot of water. If two resistance wires are used in parallel, how long does it take to boil one pot of water? Analysis: Two resistance wires are used individually or in parallel, since they are all connected to the same power supply (supply voltage is u), each resistance The voltage at both ends of the wire does not change, so the respective operating state does not change. Suppose: The resistance of a resistance wire is R_1.