For a given frequency, the deflecting torque of an induction ammeter is directly proportional to

Four ammeters $$M1, M2, M3$$ and $$M4$$ with the following specifications are available.

A current of $$1$$ $$A$$ is to be measured. To obtain minimum error in the reading, one should select meter

Two $$100V$$ full scale $$PMMC$$ type D.C voltmeter having figure of merits ($$FOM)$$ of $$10k\Omega /V$$ and $$20k\Omega /V$$ are connected in series. The series combination can be used to measure a maximum dc voltage of _______.

A $$0$$-$$10$$ $$mA$$ $$PMMC$$ ammeter reads $$4$$ $$mA$$ in a circuit. Its bottom control spring snaps suddenly. The meter will now read nearly