To measure the potential difference across the 100 resistor in the circuit shown in the figure, a voltmeter of resistance 400 is utilized. Determine the reading of the voltmeter.

Step-by-step solution

The voltmeter is connected in parallel with the 100 resistor. The equivalent resistance of the voltmeter and the 100 resistor is: R_p = 100 400 100 + 400 = 40000 500 = 80 This equivalent resistance R_p is in series with the 200 resistor. The total resistance of the circuit is: R_ eq = R_p + 200 = 80 + 200 = 280 The total current drawn from the battery is: I = V R_ eq = 84 280 = 0.3 A The reading of the voltmeter is the potential difference across the parallel combination: V_ reading = I R_p = 0.3 80 = 24 V