Three moving iron type voltmeters are connected as shown below. Voltmeter readings are $$V,$$ $${V_1}$$ and $${V_2}$$ , as indicated. The correct relation among the voltmeter readings is

The input impedance of the permanent magnet moving coil $$(PMMC)$$ voltmeter is infinite. Assuming that the diode shown in the figure below is ideal, the reading of the voltmeter in Volts is

A periodic voltage waveform observed on an oscilloscope across a load is shown. A permanent magnet moving coil $$(PMMC)$$ meter connected across the same load reads

An ammeter has a current range of $$0$$-$$5A,$$ and its internal resistance is $$0.2\Omega $$. In order to change the range to $$0$$-$$25$$ $$A$$ we need to add a resistance of