The current in a conductor and the potential difference across its ends are measured by an ammeter and a voltmeter.The meters draw negligible current.The ammeter is accurate but the vlotmeter has a zero error(that is ,it does not read zero when no potential difference is applied).Calculate the zero error if the readings for two different conditions are 1.75A, 14.4Vand 2.75a, 22.4V.

Explanation

Let the voltmeter reading when the
voltmeter has zero error be V
` ((l_1)R/(l_2)R) = (V_1/V_2)`
` rArr (1.75/2.75)=(14.4 -V/22.4 - V)`
` rArr (0.35/0.55)= (14.4-V/22.4-V)`
` 7/11 = (14.4-V/22.4-V)`
` rArr 7 xx (22.4 - V) = 11(14.4 -V)`
` rArr 156.8 - 7V = 158.4 - 11V`
` rArr (7-11) V = 156.8 - 158.4`
` rArr -4V = -1.6`
` rArr V= 0.4 V ` .