In the circuit as shown in the figure, the specifications of the two ammeters are the same. The ammeter has two ranges (0-0.6a and 0-3A). When the switch S is closed, the current flows through the resistance R1 and R2. If the pointer deflection angle of the two ammeters is the same, the ratio of R1 to R2 is () A. 1：5B. 5：1C. 1：4D. 4：1

In the circuit as shown in the figure, the specifications of the two ammeters are the same. The ammeter has two ranges (0-0.6a and 0-3A). When the switch S is closed, the current flows through the resistance R1 and R2. If the pointer deflection angle of the two ammeters is the same, the ratio of R1 to R2 is () A. 1：5B. 5：1C. 1：4D. 4：1

Because the ratio of large range to small range of the ammeter is 1:5, and A1 measures the current in the main circuit, that is, large range, the ratio of A1 to A2 is 5:1, the current in R1 is equal to the current in the main circuit minus the current in R2, that is, I1 = i-i2, and the ratio of resistance in parallel circuit is equal to the inverse ratio of current, so R1: R2 = I2: I1 = 1: (5-1) = 1:4

As shown in the figure, there are ammeters (0-0.6a, 0-3A), voltmeters (0-3v, 0-15v) on the way,
Sliding rheostat, 0-12 ohm, measured resistance, about 6 ohm, which is a power supply composed of three new batteries in series. If the experiment requires that the meter pointer does not exceed its range, and several times the measuring pointer deviates from the middle line of the meter dial, the resistance value of the rheostat connected to the circuit is at least?
A1.5 euro B.2 Euro C 2.5 euro D.3 Euro
There should be a specific description of the process

If the electromotive force of the power supply is 4.5V, the voltmeter should choose 0-3v and the resistance to be measured should be 0-0.6a. If the rheostat shares the voltage of at least 1.5V, a resistance of 3 Ω should be connected