如图所示,R1=3欧,串联后接入电路中,测得通过的电流为0.4安,伏特表的读数是6伏特,求:
(1)R1两端的电压;
(2)R2的阻值.
(1)1.2V;
(2)12Ω.
根据图片提示完成对话。
A: Where does the 1____________ come from?
B: It comes from the 2____________ .
A: Where does the cloud come from?
B: It comes from the 3____________ .
A: Where does the vapour come from?
B: It comes from the water in the 4____________ .
A: How can the water become vapour?
B: The 5____________ shines and the water becomes vapour.
A: Oh, I see.
将学校的圆形花坛按1:200画在图纸
(1)图纸上花坛的面积与实际面积的比是 [ ]
A.1:200
B.1:400
C.1:40000
D.1:628
(2)周长的比是[ ]