A 9V battery is connected to a 90Ω resistor. A voltmeter having an internal resistance of 900Ω is accidentally inserted in series between the battery and the resistor.
(a) Calculate the current in the circuit before the voltmeter is inserted.
(b) Determine the new current after the voltmeter is inserted in series.
(c) Find the reading shown by the voltmeter in this incorrect connection.
(d) Explain why the value obtained in part (c) does not represent the potential difference across the 90Ω resistor.