Science and Mathematics for Engineering 6th Edition by John Bird

Exercise 7

An ammeter has a f.s.d. of 200 mA and a resistance of 40 . The ammeter is used to measure the current in a load of resistance 400  when the supply voltage is 20 V. Calculate (a) the ammeter reading expected (neglecting its resistance), (b) the actual current in the circuit, (c) the power
dissipated in the ammeter, and (d) the power dissipated in the load.