题干

小明和他的同学通过实验探究串联电路中两个电阻消耗电功率的变化规律。他们按如图所示连接电路,电源电压保持不变,定值电阻R1为20欧。实验时,他们多次改变滑动变阻器滑片的位置,并读出各电表的示数,分别用公式计算出变阻器接入电路的电阻R2、R1消耗的电功率P1、R2消耗的电功率P2,并将计算结果及相关数据记录在如表中.

实验序号

R1(Ω)

R2(Ω)

P1(W)

P2(W)

1




20

100

0.18

1.03

2

80

0.29

1.15

3

60

0.45

1.35

4

40

0.79

1.61

5

30

1.16

1.73

6

20

1.80

1.80

7

10

3.20

1.61

8

4

4.97

1.03

(1)分析比较表中P1随R2的变化情况及相关条件,可初步得出:串联电路中,当电源电压和定值电阻R1一定时,____

(2)分析比较实验序号____ 中的数据及相关条件,可初步得出:串联电路中,当电源电压和定值电阻R1一定时,变阻器接入电路的电阻越小,变阻器消耗的电功率越小;

(3)分析比较表中P1、P2的变化情况及相关条件可发现:当变阻器接入电路中的电阻R2与定值电阻R1之前满足____时,变阻器消耗的电功率将达到最大;

(4)分析比较表中P2的数据,小组同学又有新的发现。若再增加一次实验,并使R2接入电路的电阻为5欧时,可推测P2____ W;

(5)小组同学为了验证实验所得的初步结论,决定继续探究,他们提出了以下三个初步方案,你认为合理的是____ (选填序号)。

A.更换不同电压的电源继续实验

B.更换不同阻值的定值电阻继续实验

C.改变两个电阻的连接方式继续实验。

上一题 下一题 0.0难度 选择题 更新时间:2019-08-15 05:39:00

答案(点此获取答案解析)

变阻器接入电路的电阻越小,定值电阻消耗的电功率越大,6.7与8,R1=R2,1.15,A、B 

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