题目

在“描绘小灯泡伏安特性曲线”的实验中，同学们从实验室选择了一个标有“12V  6W”字样的灯泡，                   实验器材如下：                                                                                                            电流表A1（量程300mA，内阻约为3Ω）；                                                                    电流表A2（量程600mA，内阻约为1Ω）；                                                                    电压表V（量程15V，内阻约为3kΩ）；                                                                        滑动变阻器R1（0～5Ω，额定电流为5A）；                                                                  滑动变阻器R2（0～50Ω，额定电流为0.01A）；                                                       电源E（电动势15V，内阻较小）；                                                                               单刀单掷开关一个、导线若干．                                                                                                        （1）实验器材中，电流表应该选择                                                                   ，滑动变阻器选择            ．（请选填仪表的符号） （2）画出符合实验要求的实验电路图1．                                                                    （3）描绘的伏安特性曲线如图2所示，若选取2个这样的灯泡并联，再与一个阻值为8Ω的定值电阻串联，接在电动势18V，内阻1Ω的电源两极，如图3所示，则每个灯泡消耗的电功率                           ．（请保留三位有效数字）                                                                                                                                                  答案：①A2；R1；（2）如图所示；（3）4.42．

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