Question

一电源,当外电路电阻为2.0Ω时,电流为1.0A;当外电路电阻为5.0Ω时,电流为0.5Ω,求这个电源的电动势和内阻.

Answer 1

设电源电动势为E,内阻为r,则：

1*2+1*r=E

5*0.5+0.5*r=E

解得：E=3V r=1Ω