The voltage at the circuit end measured by Voltmeter is zero, which means that () 1 external circuit is open circuit, 2 external circuit is short circuit, 3 current on external circuit is relatively small, 4 resistance in circuit is zero

The voltage at the circuit end measured by Voltmeter is zero, which means that () 1 external circuit is open circuit, 2 external circuit is short circuit, 3 current on external circuit is relatively small, 4 resistance in circuit is zero

It's 1

Using a voltmeter to measure the voltage of the circuit terminal is 0V, which means that the external circuit a is open circuit, the external circuit B is short circuit, the current of the external circuit C is relatively small, and the internal resistance of the power supply D is 0
The title is wrong. It should be to measure the voltage of the circuit terminal with a voltmeter

The electromotive force of the power supply is 2V and the internal resistance is 1 ohm. When the external circuit is open, what are the voltages of the power supply and the power supply terminal in the circuit

What a mess you are thinking about
When the circuit is disconnected, the electromotive force of the power supply is still 2V, and the voltage of the power supply terminal is also 2V
Because, when the circuit is disconnected, if you want to measure the power supply voltage, it can only be an ideal voltmeter (internal resistance is infinite), then there is no current in the circuit, and the terminal voltage = the power supply electromotive force

When measuring the voltage with a voltmeter, is the bulb under the voltmeter on? Is connecting the voltmeter equivalent to a short circuit?

Answer: on, not short circuit
Analysis:
The presence of a voltmeter does not affect the connection of the circuit
Therefore, the lamp is still the same as before, and it is on; at the same time, because the resistance of the voltmeter itself is very high, when we usually consider the "insulator" treatment, the insulator is connected to both ends of the lamp, the current only goes through the lamp, the lamp is normal, not short circuit