Question

Circuit shows the method of Measurement of low resistance by Ammeter-Voltmeter method. What is the percentage error?

(a) Zero

(b) \(\frac{R_x}{R_x + R_v}\) × 100

(c) \(– \frac{R_x}{R_x + R_v}\) × 100

(d) \(– \frac{R_v}{R_x + R_v}\) × 100

The question was asked in an online interview.

I'd like to ask this question from Advanced Problems on Measurement of Low Medium and High Resistance topic in division Measurement of Resistance of Electrical Measurements

Answer 1

The correct choice is (c) \(– \frac{R_x}{R_x + R_v}\) × 100

Easiest explanation: Percentage Error = \(\frac{R_m  – R_x}{R_x}\) × 100

\(= \frac{R_x R_v – R_x(R_x-R_v)}{R_x (R_x+R_v)}\) × 100

∴ Percentage Error = \(– \frac{R_x}{R_x + R_v}\) × 100.