Final answer:
When measuring very large currents, low resistance and high power rating ammeters are required. A shunt resistor is used to divert most of the current, with a small fraction flowing through the ammeter. By using the output voltage of an op amp, the load current can be calculated.
Step-by-step explanation:
When measuring very large currents, ammeters of very low resistance and high power rating are required. A shunt resistor is placed in series with the current to be measured. The shunt resistor acts as a current divider, with most of the current flowing through it and only a small fraction flowing through the ammeter. The output voltage of the op amp is used to calculate the high load current being measured.
In this case, the output voltage of the op amp is given as 4.80 V. By knowing the relationship between the shunt resistor, the ammeter resistance, and the output voltage, we can calculate the high load current.