How to judge whether the ammeter in the circuit diagram is an ammeter or a voltmeter

How to judge whether the ammeter in the circuit diagram is an ammeter or a voltmeter

1 is a v-voltmeter and a-ammeter
2. V range 0 ~ 3V / 0 ~ 15V
A range 0 ~ 0.6 / 0 ~ 3A
3. Parallel connection of voltmeters
Ammeter in series
4. The ammeter should not be directly connected with the power supply (it is necessary to use electrical appliances) or connected in parallel with the power supply
The voltmeter can be connected in series with the power supply

A classmate used a power supply (unknown voltage), two switches, an ammeter, a sliding rheostat (20 Ω 2a) and several wires to measure the power of the bulb. The small bulb was only marked with the word 0.2A. The rated voltage was not clear. After thinking, he designed and connected the circuit. During the experiment, he found that the small bulb could light normally when the scribe P of the sliding rheostat was at the midpoint The student measured the rated power of the small bulb
Calculate the rated current of 1 small bulb, 2 draw the experimental figure, 3 write out the steps of measuring the rated electric power, the calculation process of the measured physical quantity and the mathematical expression of the rated electric power

1. Rated current of small bulb I = 0.2a2, take out a switch S2, connect all components in series (switch S1), and then connect the switch to both ends of small bulb in parallel. 3. Assemble the circuit according to the above method. Only close S1, slide the slice P of rheostat to the midpoint (R0 = 10 Ω), so that the current expression number is I = 0.2A

In the circuit shown in the figure, the power supply voltage is 15 V and does not change, and the sliding rheostat R2 is marked with "20 Ω 2 a". After closing the key, the current indication is 0.2 a, the voltage indication is 2 V, and the existing resistance values are 15 Ω and 24 Ω. Please choose one to replace the resistance R1. Requirements: in the process of moving the slide P of the rheostat, The ammeter and voltmeter can reach the maximum value of a certain range, and the circuit can work normally
(1) What ohm of resistance should be selected?
(2) When the above requirements are met, the rheostat R2 is connected to the resistance range of the current
The circuit can work normally, that is to say, it does not exceed the maximum range of the meter and the maximum current of the sliding rheostat. It's just soy sauce.

How do you think this doesn't work? To make the ammeter and voltmeter reach the maximum value of a certain range, both of them are OK. 15 ohm R2 resistance is 3.75 ohm, voltage is 3V, resistance is 10 ohm, current is 0.6A; 24 ohm R2 resistance is 6 ohm, voltage is 3V, resistance is 1 ohm, current is 0.6A, How to calculate that the circuit can work normally? If 0.2A is needed, it can't be achieved. If it doesn't exceed the maximum current of the sliding rheostat, even if the circuit can work normally, both of them can. I'm thinking about it. If you know what the circuit can work normally, tell me and I'll help you solve it, Both of them are OK, because if the sliding rheostat resistance is 0, the current of 15 Ω is 1a, and that of 24 Ω is 0.625a. At this time, the current is the maximum. The current will never exceed the range of the ammeter and the maximum current of the sliding rheostat. If I can go to tomorrow, I'll ask the teacher. He didn't respond on the pig's QQ. I already know that now