Final answer:
Null measurements can be more accurate than measurements using standard voltmeters and ammeters. Other factors that can limit the accuracy of null measurements include resistance in wires and connections, and temperature variations in resistance. However, using a digital device that is more sensitive than a galvanometer can improve the accuracy of null measurements.
Step-by-step explanation:
Null measurements can be more accurate than measurements using standard voltmeters and ammeters. One factor that can limit the accuracy of null measurements is resistance in the wires and connections, which can never be completely eliminated.
Another factor is temperature variations in resistance, although this can be reduced by using appropriate materials. However, the use of a digital device that is more sensitive than a galvanometer can improve the accuracy of null measurements because it allows for the measurement of smaller currents.