[SOLVED] Voltage and Current 1. The problem statement, all variables and given/known data A d.c. circuit has a 20ohm resistor and ammeter connected in series. A voltmeter is connected in parallel to the resistor. After some time, the reading on the ammeter suddenly decreases to nearly zero, but the voltmeter reading remains at 4V. Suggest a possible reason for this. 2. The attempt at a solution I know that a voltage reading can still be obtained if the switch is opened. However, the reading is said to decrease almost to zero. Can somebody please explain this?