NBSω |
R+r |
NBSω | ||
|
| ||
2(R+r) |
A.②③ | B.②④ | C.③④ | D.①④ |
NBSω |
R+r |
Em | ||
|
E |
R+r |
NBSωR | ||
|
NBSω | ||
|
| ||
2(R+r) |
A.使线圈匝数增加一倍 |
B.使线圈面积增加一倍 |
C.使线圈匝数减少一半 |
D.使磁感应强度的变化率增大一倍 |
A.5
| B.5A | C.3.5
| D.3.5A |
A.电路中交变电流的频率为0.25Hz | ||
B.用交流电流表测得通过电阻的电流为
| ||
C.电阻消耗的电功率为2.5W | ||
D.用交流电压表测得电阻两端的电压是5V |
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