(20 1 1? Please select some of the following devices to measure the internal resistance of voltmeter and electromotive force of power supply: ⅰ. Voltmeter to be tested: range Um=

(1) Microammeter has a small range and cannot be connected to the circuit.

The physical circuit is as shown in the figure:

(2) After the connection is completed, turn off the switch and adjust the resistance box. When the voltmeter pointer points to full bias, read the resistance of the resistance box, as shown below:

r 1 = 2000.00ω；

According to the ohm's law of closed circuit, the equation is listed: E=UmR? vR 1+Um

When the voltmeter pointer points to half bias, the resistance of reading resistance box is R2 = 6000.00ω. ..

According to the ohm's law of closed circuit, the equation is listed: E= 12×UmR? vR2+ 12×Um

Where Um=3V, r 1 = 2000.00ω, 6000.00ω.

Solution: E=6V, RV = 2kω.

So the answer is: (1) as shown in the figure;

(2)2kω； 6V。