A. white B. orange C. pencil D. pen E. green
Hi, I'm Lucy. I have a pencil box. It's ____ I have a ____ It's black. I have an eraser. It's ____ I have a ____ It's red. I have a crayon. It's____
You must pay attention to the traffic lights.
在图中,水平导线中有电流I通过,导线正下方的电子初速度的方向与电流I的方向相同,则电子将( )
导线代号
A
B
C
D
E
F
G
长度(m)
1.0
0.5
1.5
1.2
横截面积(mm2)
3.2
0.8
材料
锰铜
钨
镍铬丝