Question

                                 

（1）有一電阻值約為20Ω、額定功率約為7.2W的電阻，現(xiàn)準(zhǔn)備用伏安法測量多組數(shù)據(jù)，借助I﹣U圖象較準(zhǔn)確地測其阻值，實(shí)驗(yàn)室提供的器材有：                                                                                                    

A．電流表（量程O～3A，內(nèi)阻約O.1Ω）                                                                       

B．電流表（量程0～0.6A，內(nèi)阻約0.5Ω）                                                                      

C．電壓表（量程0～3V，內(nèi)阻約3kΩ）                                                                         

D．電壓表（量程O～15V，內(nèi)阻約15kΩ）                                                                     

E．滑動變阻器（阻值O～10Ω，額定電流2A）                                                              

F．直流電源（電動勢12V，內(nèi)阻不計(jì)）                                                                          

G．開關(guān)及導(dǎo)線若干                                                                                                        

①要使測量誤差盡量小，電流表應(yīng)選擇                                                       ，電壓表應(yīng)選擇      ．（填序號字母）        

②按實(shí)驗(yàn)要求在圖1中畫出實(shí)驗(yàn)電路圖．                                                                        

（2）利用如圖甲所示電路測量電池組的電動勢E和內(nèi)阻r．根據(jù)實(shí)驗(yàn)數(shù)據(jù)繪出1/I﹣R圖線如圖乙所示，其中R為電阻箱讀數(shù)，I為電流表讀數(shù)，不計(jì)電流表內(nèi)阻，由此可以得到E=                          ，縱截距與電動勢的乘積表示的意義            ，數(shù)值和單位為                                                                                          

                                                                                                                                       

Answer 1

（1）①BD；②電路圖如圖所示；（2）2V；電源內(nèi)阻；1Ω；