In the circuit shown in the figure, the power supply voltage is 3V. When the switches S1 and S2 are closed, then () A. The indication of voltmeter is 3vb. Lamp L1 is not on, lamp L2 is on. C. ammeter will be burned out. D. both bulbs will be burned out

In the circuit shown in the figure, the power supply voltage is 3V. When the switches S1 and S2 are closed, then () A. The indication of voltmeter is 3vb. Lamp L1 is not on, lamp L2 is on. C. ammeter will be burned out. D. both bulbs will be burned out

It can be seen from the circuit diagram that when the switches S1 and S2 are closed, the two bulbs and the voltmeter are short circuited, the current starts from the positive pole, passes through the ammeter, and directly returns to the negative pole of the power supply, ∵ when the electric appliance is short circuited, it can not work, ∵ the two bulbs are not on and will not be burned out, and the voltmeter has no indication, so the abd is incorrect, ∵ when the power supply is short circuited, the current is too large, it will burn out the power supply and the ammeter, ∵ the current is too The watch will be burnt out, so C is correct