如图所示,电源电压为12V且保持不变,R1=4Ω,电路中的电流为1A。求: (1

题型:计算题

问题:

如图所示,电源电压为12V且保持不变,R1=4Ω,电路中的电流为1A。求:

(1)R1两端的电压;

(2)R2的阻值。

考点:欧姆定律及其应用
题型:计算题

动词填空 可适当填加助动词或情态动词。

      Last Sunday, my friends Wang Tao, Zhang Jun asked me to go    1     (swim) with them. Soon we got

to the river. They were swimming in it. But I couldn't swim. So I    2    (sit) under a big tree and watching

a little boy    3    (play) with a ball near the river. But the ball    4    (fall) into the water and he fell into the

water, too.

      I was standing up and    5    (call) for help. But my friends    6    (be) far from me and they    7    (not

hear). So I jumped into the water. I didn't know how to swim in it, but I    8    (take) the little boy out of the

water. His parents thanked me very much. They said, "You are a good boy, a good young pioneer."

     When my friends knew this, they all smiled and    9    (say), "You    10    (swim) now."

1._____ 2._____ 3._____ 4._____ 5._____

6._____ 7._____ 8._____ 9._____ 10._____

题型:计算题

贫血伴骨髓外含铁血黄素颗粒和铁粒幼细胞明显减少的最可能的诊断是()。

A.溶血性贫血

B.铁粒幼细胞性贫血

C.缺铁性贫血

D.再生障碍性贫血

E.营养性巨幼细胞性贫血

题型:计算题

常压下二氧化硅的有那些结晶态?

题型:计算题

契税实行( )的幅度税率。

A.2%~3%

B.3%~5%

C.4%~5%

D.5%~6%

题型:计算题

有50mL含Ca2+5.0μg的溶液,用10.0mL二苯硫腙一氯仿溶液萃取(萃取率为100%).在518nm处用1.00cm吸收池测得百分透射比为44.5。计算:(1)质量吸光系数a;(2)摩尔吸光系数ε。(已知MCa=40.078g/mol)

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