Question

A resistor R is connected across a 120 V supply. A voltmeter of 10,000 ohms resistance is connected between the center of the resistor and one side of the supply and reads 40 V. What is the value of the resistance R?

Answer 1

According to Given data, the connection is as below. + 80V 120 V 40 um A -t î, = 10,000 wann + € * مع دمع yov 10,000.12 40V (9-11) (1-4mA) let si be the current passing through The Veltmeter, and that is 1, 40V 4MA. 10,000 Now, Lower R 2 region gets you as it is parallel with voltmeter Νοιώ R 2 Upper region gets (-120V - 400) = 80 V Supply. let I be the total drawing Current, then lower 1-1, Pe 1-4mASo, draws 80 V = 1. R 2 . 40 V = (1-uma) 80 = (1 - 4x10R I = 160 R from & og ☺ -3 80 = 160 -3 4x10 R 80 160 4x108 ) R * uxio'r = 80 R= 20,000