问题
选择题
— What ______ your bike yesterday?
— It didn't work. [ ]
A. was happened in
B. happened in
C. was happened to
D. happened to
答案
答案：D
搜题请搜索小程序“爱下问搜题”
— What ______ your bike yesterday?
— It didn't work. [ ]
A. was happened in
B. happened in
C. was happened to
D. happened to
答案：D
在测定水果电池的电动势和内阻时，某实验小组选取相同的实验器材，分别用甲、乙两种电路进行实验．其中一种电路测得的实验数据作出的U-I图线，如图丙中图线1所示，另一电路测得的实验数据如下表．
| I/mA | 0.50 | 0.60 | 0.70 | 0.80 | 0.85 | 0.90 |
| U/V | 0.45 | 0.35 | 0.25 | 0.15 | 0.10 | 0.05 |
（1）请用表中数据在丙图坐标纸上描点，并作出U-I图线．
（2）图线1所对应实验电路是______（选填“甲”或“乙”）．
（3）消除电表内阻产生的误差，电源的电动势E=______V，电源的内电阻r=______Ω．