When measuring the electric power of small bulb, considering that the ammeter and voltmeter have certain resistance, should the measured value of electric power of small bulb be larger than the real value

When measuring the electric power of small bulb, considering that the ammeter and voltmeter have certain resistance, should the measured value of electric power of small bulb be larger than the real value

It's smaller than the real one. Because voltage * current = power and I = u / R, when the voltage is constant, the larger the resistance is, the smaller the current is

In the circuit diagram of measuring resistance by the same volt ampere method, when the indication of ammeter is 0 before closing the switch, the indication of voltmeter is 6V
When the switch is closed, the pointer of the ammeter deflects to the left, and the indication of the voltmeter is still 6V
Complete version: in the circuit diagram of measuring resistance by voltammetry, when the indication of ammeter is 0 before closing the switch, the indication of voltmeter is 6V. When the switch is closed, the pointer of ammeter deflects to the left, the indication of voltmeter is still 6V. The reason is: and

The positive and negative poles of ammeter are connected reversely
Two tables are connected in series

Connect a lamp, voltmeter and ammeter in series into the circuit. How does the number of ammeter and voltmeter change after closing the switch

1) The resistance of the ammeter is very small, equivalent to a wire;
2) The resistance of the ammeter is very high, which is equivalent to an open circuit
3) According to Ohm's law formula I = u / R, the total resistance is very large and the current is very small when the power supply voltage is constant, so the ammeter pointer does not move, so the ammeter indicator is 0A and the bulb is not on
4) In the series circuit, the current is equal. According to I = u / R, the voltage is proportional to the resistance, and almost all the voltage in the circuit is shared by the voltmeter, so the indication of the voltmeter is very close to the power supply voltage