Question

为了测量量程为3V的电压表V的内阻（内阻约2000Ω），实验室可以提供的器材有：                       

电流表A₁，量程为0.6A，内阻约0.1Ω                                                                             

电压表V₂，量程为5V，内阻约3500Ω                                                                             

变阻器R₁阻值范围为0﹣9999Ω                                                                                      

变阻箱R₂阻值范围为0﹣99.9Ω                                                                                       

滑动变阻器R₃，最大阻值约为100Ω，额定电流1.5A                                                       

电源E，电动势6V，内阻约0.5Ω                                                                                    

单刀单掷开关K，导线若干．                                                                                          

                            

（1）请从上述器材中选择必要的器材，设计一个测量电压表V的内阻的实验电路，在图1方框中画出电路原理图  （    电路原理图中的元件要用题中相应的英文字母标注），要求测量尽量准确．                

（2）根据你所画的电路原理图在图2所给的实物图上画出连线．                                   

（3）说明实验所要测量的量：                                                                           ．写出计算电压表V的内阻R_V的计算公式为R_V=                                                                                                                ．

                                                                                                                                       

Answer 1

（1）（2）

（3）电压表V的示数U、电压表V₂的示数U₂、电阻箱R₁的读数r₁，电压表的内阻为R_v=