The rest positions of the needles in a miliammeter and voltmeter not in use are as shown in (Fig. 3.61)(a). When a student uses these in his experiment, the readings of the needles are in the positions shown in (Fig. 3.61)(b). Find the corrected values of current and voltage in the experiment.
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Explanation

As zero correction in milliammeter `= 4 mA` , the correct value of current is `38 mA + 4 mA = 42 mA`. Further, as zero correction in voltmeter `= - 0.4 V`. The correct value of voltage is `3.6 V - 0.4 V = 3.2 V`.