In the circuit as shown in the figure, the power supply voltage remains unchanged, and the resistance R2 = 2r1. Suppose that the electric power of resistance R2 is P1 when switch S2 is closed and S1 is open, and the electric power of resistance R2 is P2 when both switches S1 and S2 are closed, then the electric power P1: P2=______ At this time, the electric power of resistance R1 is equal to______ Tile

In the circuit as shown in the figure, the power supply voltage remains unchanged, and the resistance R2 = 2r1. Suppose that the electric power of resistance R2 is P1 when switch S2 is closed and S1 is open, and the electric power of resistance R2 is P2 when both switches S1 and S2 are closed, then the electric power P1: P2=______ At this time, the electric power of resistance R1 is equal to______ Tile

When switch S2 is closed and switch S1 is open, R1 and R2 are connected in series. According to the resistance series and Ohm's law, the current in the circuit can be calculated. ∵ the total resistance in the series circuit is equal to the sum of the partial resistances. According to Ohm's law, the current in the circuit is I = ur1 + R2 = u12r2 + R2 = 2u3r2, and the electric power of resistance R2 is P1 = i2r2 = (2u3

The voltage at both ends of the power supply remains unchanged, and the resistance of R2 and R3 is 10 Ω. Close switch s and open switch S1

(1) When s is closed and S1 is disconnected, R1 and R2 are connected in parallel, A1 is used to measure the main circuit current, A2 is used to measure the R2 current
That is: the main current and R2 current are 3:1
The ratio of R1 current to R2 current is 2:1
It is concluded that R1: R2 = 1:2
So: R1 = 5 Ω
(2) When the ammeter is replaced by an ammeter, three resistors are connected in series
R1:R2:R3=1:2:2
Then: the voltage ratio of the two ends of the three resistors is 1:2:2
At this time, V1 measures the voltage of R2 and R3, V2 measures the voltage of R1 and R2
So: U1: U2 = 4:3
Question 16: the answer is a BD
The answer provided later must be wrong