When a student was doing the experiment of measuring the resistance of a small light bulb, he connected the circuit, closed the switch and found that the light bulb did not emit light (1) When doing the experiment of measuring the resistance of a small bulb, a student connected the circuit, closed the switch, and found that the bulb did not emit light, the ammeter showed the number, and the voltmeter did not show the number. After inspection, it was found that there was only a fault at the bulb, so the reason for the above phenomenon may be () (2) When doing the experiment of measuring the resistance of a small bulb, a student connected the circuit and closed the switch. He found that the bulb was not on, the ammeter did not show the number, and the voltmeter had a large number. The reason for the above phenomenon may be () Urgent, must tell me why, by the way, short circuit, open circuit and other differences

When a student was doing the experiment of measuring the resistance of a small light bulb, he connected the circuit, closed the switch and found that the light bulb did not emit light (1) When doing the experiment of measuring the resistance of a small bulb, a student connected the circuit, closed the switch, and found that the bulb did not emit light, the ammeter showed the number, and the voltmeter did not show the number. After inspection, it was found that there was only a fault at the bulb, so the reason for the above phenomenon may be () (2) When doing the experiment of measuring the resistance of a small bulb, a student connected the circuit and closed the switch. He found that the bulb was not on, the ammeter did not show the number, and the voltmeter had a large number. The reason for the above phenomenon may be () Urgent, must tell me why, by the way, short circuit, open circuit and other differences

(1) Short circuit (too high voltage causes voltmeter failure)
(2) Open circuit (the voltmeter is connected in parallel to the consumer, so the voltage can be detected)
Short circuit: current or voltage too high
Short circuit: the circuit doesn't work

As shown in the figure, the voltage at both ends of the power supply remains unchanged, and the resistance value of resistance R1 is 2 Ω. Close switch S. when slide P of sliding rheostat is located at point a, the indication value of voltmeter V1 is 4V, and that of voltmeter V2 is 10V. When slide p of sliding rheostat is located at point B, the indication value of voltmeter V1 is 8V, and that of voltmeter V2 is 11V______ W．

(1) According to the constant total voltage, the indication of voltmeter V2 and the voltage at both ends of R1 should be the power supply voltage. The indication of voltmeter V1 and the voltage at both ends of resistance R2 are also the power supply voltage. U = 10V + i1r1 = 11V + i2r1 -------- ① u = 4V + i1r2 = 8V + i2r2 -------- ② R1 (i1-i2