An ammeter and a voltmeter are used to measure the current in a conductor and the potential difference across its terminals. Both meters draw negligible currents. The ammeter is perfectly accurate, whereas the voltmeter possesses a zero error (meaning it fails to read zero when no potential difference is present). Determine the zero error if the readings under two distinct conditions are 1.75 A , 14.4 V and 2.75 A ,

Step-by-step solution

Let R be the resistance of the conductor and e be the zero error of the voltmeter. The true potential difference across the conductor is given by Ohm's law as V = IR . The voltmeter reading is V' = V + e = IR + e . Using the given readings, we can write two equations: 14.4 = 1.75 R + e 22.4 = 2.75 R + e Subtracting the first equation from the second yields: 22.4 - 14.4 = (2.75 - 1.75) R 8.0 = 1.0 R R = 8.0 Substituting the value of R into the first equation: 14.4 = 1.75 8.0 + e 14.4 = 14.0 + e e = 0.4 V