【单选题】Which one is not the reason why Afghanistan government can not eliminate opium quickly?
A.
Opium is closely related with the economy situation of Afghanistan people
B.
It is a hard job which needs time
C.
Afghanistan is not a democratic country
D.
It is a problem left by history and it need more patience
【单选题】在RLC串联电路中,产生串联谐振时,回路的总电抗Z等于()。
【简答题】附图中A、B间电压U=100V,R 1 =1Ω,R 2 =3Ω, =4Ω, ,求以A、B为端点的二端网络的复阻抗、阻抗、阻抗角以及电流i和电压 u AD 。的有效值.
【单选题】下列有关薪酬优点的描述属于技能或能力薪酬的是( )
【单选题】电路如图所示,下列各式中错误的是 ( )
A.
I 5 + I 6 - I 7 + I 8 = 0
B.
R 1 I 2 + E 1 - R 4 I 4 + R 3 I 3 - R 2 I 1 + E 2 = 0
C.
U ad =- E 2 + R 2 I 1 - R 3 I 3 = R 1 I 2 + E 1 - R 4 I 4
【单选题】如下哪一个问题是解线性方程组
A.
已知系数 a,b,c 求抛物线 y= ax2+bx+c 与x轴的交点坐标。
B.
已知抛物线 y=ax2+bx+c 上三点的坐标,求a,b,c.
【单选题】RLC串联谐振电路中,电阻两端电压____总电压,电感与电容两端电压相等,相位相反,且为总电压的____倍,谐振阻抗表达式为______。
【单选题】在图示电路中,已知R=5Ω,XL=15Ω,Xc=3Ω,U=15V,则总电流I为( )。
【单选题】Which one is NOT the reason for the airtight security at the data center?
A.
There are dangers posed by hackers.
B.
There is only one Visa center in North America.
C.
There is considerable growth in mobile purchases.
D.
There are a large number of daily transactions processed here.