Question

two resistors each with a resisance of 5 x 10⁶ are connected in series to a 45 V power supply whose internal resistance is negligible. You connect a voltmeter across one of these resistors, and this voltmeter has an internal resistance of 1.8 x 10 ohms. What is the reading on the voltmeter?

Answer 1

The voltmeter reads 22.5 V when placed across one of the two resistors in series in the circuit.

Step-by-step explanation:

When two resistors each with a resistance of 5 x 10¶Ω are connected in series to a 45 V power supply and a voltmeter with an internal resistance of 1.8 x 10¶Ω is connected across one of these resistors, the total resistance in the circuit is the sum of the two series resistors plus the resistance of the voltmeter. The voltmeter, being in parallel to one of the resistors, will not affect the total resistance. The voltage drop across each resistor can be found by dividing the total voltage by the number of resistors since they have identical resistances. The reading on the voltmeter will therefore be half of the supply voltage, which is 22.5 V.