Test Preparation on Current Electricity-IV-Physics Test Series For NEET 2020

A circuit contains an ammeter, a battery of 30 V and a
resistance 40.8 ohm all connected in series. If the ammeter
has a coil of resistance 480 ohm and a shunt of 20 ohm, the
reading in the ammeter will be

A potentiometer wire is 100 cm long and a constant
potential difference is maintained across it. Two cells are
connected in series first to support one another and then in
opposite direction. The balance points are obtained at 50
cm and 10 cm from the positive end of the wire in the two
cases. The ratio of emf’s is

A galvanometer can be used as a voltmeter by connecting a