Generally speaking, when the load resistance decreases, the load increases, and the power output power increases (×), how to explain

Generally speaking, when the load resistance decreases, the load increases, and the power output power increases (×), how to explain

"Load resistance decreases, power output increases" is correct. But "load increases" is a vague statement, because it is difficult to define whether the meaning of "load increases" is "load resistance increases" or "load increases". In fact, the two ideas are just the opposite

When the E and R of the power supply are constant and the external resistance is pure resistance, under what conditions is the output power of the power supply the maximum? What is the efficiency of the power supply at this time?

When the external resistance is as large as the internal resistance of the power supply, the output power of the power supply is the largest, and the efficiency of the power supply is 50%

The resistance of a section of conductor is increased by 3 ohm. When it is connected to the power supply, it is found that the current passing through is 0.8 times of the original one?

U/R=I,U/(R+3)=0.8I;R=12

An electric bell has a resistance of 10 ohm, and the voltage is 6V when it works normally. Now there is only a 9V power supply. Q: how many ohm fixed value resistors need to be connected in series?
I calculated it according to the power, which is 12.5 euro, but most of my classmates calculated it as 5 euro. I'm a little confused,

The normal working current is 6V 10 Ω, that is to say, the normal working current is I = 6 / 10 = 0.6A
When working at 9V, the resistance required to maintain 0.6A current is r = u / I = 9 / 0.6 = 15 Ω
So it should be 5 Ω more than the original 10 Ω