A.电源输出功率逐渐变大 |
B.电源的输出功率先变小后变大 |
C.电源内部消耗的功率逐渐变小 |
D.滑动变阻器R消耗的功率逐渐变小 |
E |
R0+r+R |
E2 | ||
(R0+R)+2r+
|
E2 | ||
(r+R)+2r+
|
r2 |
r+R |
E |
R0+R+r |
E |
R0+r+R |
E |
2r+R |
E2 | ||
4r+R+
|
4r2 |
R |
A.干路中电流不断增大 |
B.R1上消耗的电功率不断增大 |
C.R1上消耗的电功率不断减小 |
D.R2上消耗的电功率不断减小 |
A.8J | B.4J | C.16J | D.1J |
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