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In the series circuit of constant value resistor, sliding rheostat and ammeter, the voltmeter is connected in parallel at both ends of the resistor. If the voltage expression is 0 during the experiment, If the current indicator is 0 and the voltage indicator increases suddenly, what fault will happen?
If the voltage indication number is 0 and the current indication number does not change during the experiment, the fault is: there is an open circuit at the connection between the voltmeter and the resistance (at least one end is not well contacted), and the other parts are well contacted (because the indication number of the ammeter does not change). If the current indication number is 0 and the voltage indication number suddenly increases, the fault is
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