When (1)P is at point A, the resistance is large, the current is small, the V2 indication should be small, and the measured actual data is large, indicating that the voltmeter is faulty;

(2) From the circuit diagram, we can only know the voltage and current across R3; So only the resistance of R3 can be found;

According to ohm's law:

Resistance R3=U 1A 1? A2 = 20Ω

According to ohm's law of closed circuit, E=3.20+0.42(r+R 1).

E=2.80+0.48(r+R 1)

Simultaneous solution: E=6V, because R 1 is unknown, so the internal resistance cannot be obtained;

So the answer is:

( 1)V2；

(2) resistor R3; R3 = 20Ω

(3) The magnitude of electromotive force E can be found, but the magnitude of internal resistance R cannot be found; E=6V。