“由一道物理竞赛题引出的…”一文(99年2期).对该文推出的结论表示赞同.但 t_串=t_1+t_2+…+t_n,1/t_并=1/t_1+/t_2+…+1/t_n 是在 n个电热丝发热均供给液体吸收的情况下成立.故由此解答其所举例2得出了错误答案,因例2中的 R_0的热效应并未用来加热容器中的水.原例2正解应为:原例2:如图示装置中,电源电压不变.三个相同的电热丝浸在盛水容器.在换档开关每换档时,容器内都盛有质量和 “The article entitled ”..." from a physics contest (1999 issue 2) agrees with the conclusion of the article. But t_string=t_1+t_2+...+t_n, 1/t_and=1/t_1+ /t_2+...+1/t_n is established when n heating filaments are all absorbed by the liquid supply. Therefore, the solution given in Example 2 leads to a wrong answer, because the thermal effect of R_0 in Example 2 is not used for heating. The water in the container. The original solution of the original case 2 should be: The original example 2: In the device shown in the figure, the power supply voltage is not changed. Three identical heating wires are immersed in the water container. During each shift of the shift switch, the inside of the container Both are quality and