如圖所示電源的電壓為U,R1=12Ω,R2=6Ω,開(kāi)關(guān)S閉合后,電流表A1和A2的讀數(shù)之比為( ) A.1:3 B.3:1 C.2:3 D.3:2
如圖所示電源的電壓為U,R
1=12Ω,R
2=6Ω,開(kāi)關(guān)S閉合后,電流表A
1和A
2的讀數(shù)之比為( )
![](http://hiphotos.baidu.com/zhidao/pic/item/30adcbef76094b36b78b796aa0cc7cd98d109d1f.jpg)
A. 1:3
B. 3:1
C. 2:3
D. 3:2
物理人氣:216 ℃時(shí)間:2019-08-17 20:07:17
優(yōu)質(zhì)解答
從圖可知,電阻R
1、R
2并聯(lián),電流表A
1測(cè)量通過(guò)R
2的電流,電流表A
2測(cè)量干路電流,
∵電阻R
1、R
2并聯(lián),
∴U
1=U
2=U,
又∵I=
,
∴
=
=
×
=
=
=
,
∵I=I
1+I
2,
∴
=
=
=
,
即:電流表A
1與A
2讀數(shù)之比為2:3.
故選C.
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