电流源电路的特点是输出电流恒定,交流等效电阻()
A.等于零
B.比直流等效电阻小
C.等于直流等效电阻
D.远远大于直流等效电阻
参考答案:D
在图中,导体A、B是由同种材料做成的,A和B等长,但A比B的横截面积大,当S闭合后,在相同时间下,下列叙述正确的是
A、电流通过A、B所做的功是WA>WB
B、电流通过A、B所做的功是WA<WB
C、电流通过A、B所做的功是WA=WB
D、无法比较电流通过A、B时做功的大小
用所给单词的适当形式填空。
1. My best friend is from __________ (Japanese).
2. This is the __________ (begin) of the garden tour.
3. The koalas often sleep during the day and eat __________ (leaf) at night.
4. Don't play football in the street. It's __________ (danger).
5. Are they __________ (friend) to you?