12.2 Problems
547
Fig. 12.20
12.2.4 Kirchhoff’s Laws
12.40 A moving coil meter has a full scale reading of 1 mA and a resistance of
80 . How could the meter be used to measure (a) 100 mA full scale and
(b) 80 V full scale?
[University of Manchester]
12.41 A pocket voltmeter has a resistance of 120 . What will it read when connected to a battery of emf 9 V and an internal resistance 15 ?
[University of Oxford]
12.42 When a galvanometer is shunted with a 1 resistance, only 1% of the main
current passes through it. What is the resistance of the galvanometer?
12.43 A 10 V battery, having an internal resistance of 1.0 , is joined in parallel
with another of 20 V and internal resistance of 2 . Calculate the current
flowing through each battery, and the rates of expenditure of energy in the
two batteries and the 30 resistance (Fig. 12.21).
[University of Cambridge]
Fig. 12.21
12.44 A battery of emf 1 V and internal resistance 2 is connected to another
battery of emf 2 V and internal resistance 1 in parallel with an external
resistance of 10 . Find the currents?