题图所示交流电路,当ω=1000rad/s时发生谐振,已知端口总电压有效值U=180V。求电容C值及端口电流有效值I。
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Based on the passage, which of the following statements can best describe the side effects
About 5 to 10 percent of children experience mild temporary side effects.
B. Side effects of a flu vaccine will usually last for a very long period of time.
C. If a child has never been infected by flu, he or she is more likely to have side effects
D. If a person has been exposed to the influenza virus before, he or she will not have side effects
What should be implied when people give and receive presents?
A. Cheap presents should be given to the inferiors and higher-priced to the superiors
B. Presents are a sign of affection or friendship and should be appropriate.
C. Presents to friends should be the same as those to colleagues.
D. The more costly the presents are, the more respect guests receive.
正弦交流电路如图所示,L1=1H,L2=2H,M=0.5H,ω=1000rad/s。问C为何值时此电路发生谐振?
According to the passage, which of the following reasons why only the most determined travelers can see the best of the national parks is NOT mentioned?
A. Infrastructural development in these areas is limited.
B. The ski resorts do not have the same number of lifts as their European counterparts
C. Roads are of poor quality in the south.
D. The mountains are too tall for the tourists to climb.