How to judge which electric appliance or circuit is measured by Voltmeter and ammeter

To see which part of the circuit the voltmeter is connected in parallel with, it measures the voltage at both ends of that part of the circuit;
To see which part of the circuit the ammeter is connected in series with, it measures the current through that part of the circuit
In the figure, V measures L1
A. measure the total current

Draw the circuit diagram of using voltmeter, ammeter and sliding rheostat to measure the electromotive force and internal resistance of power supply

Here you are

Are voltmeters and ammeters equal to one wire in the circuit?

The ammeter is regarded as a wire in the circuit, but the voltmeter is not. The resistance of the voltmeter in the circuit is regarded as infinite, which can also be said to be open circuit. Therefore, the ammeter should be connected in series in the circuit, and the voltmeter should be connected in parallel in the circuit, so it can work normally

In the voltammetric resistance measuring circuit shown in the figure, the internal resistance of the voltmeter is 3K Ω and the reading is 3V; the internal resistance of the ammeter is 10 Ω and the reading is 4mA. The real value of the resistance R to be measured is equal to ()
A. 750ΩB. 760ΩC. 1000ΩD. 1010Ω

According to Ohm's Law: UI = 3v4ma = 750 Ω = r true, RVR true + RV solution: r true = 1000 Ω, so choose C

How to judge which electric appliance or circuit is measured by Voltmeter and ammeter