Answer :
The dial indicator used in the shaft-deflection method does not interfere with loosening the anchor bolts, making the statement false. Other factors that can limit the accuracy of null measurements include environmental conditions and the quality of the measurement setup. A more sensitive digital device could improve accuracy if it has better precision, resolution, and noise rejection. So, the correct option is - true.
When using the shaft-deflection method of measuring soft foot, the statement that the dial indicator may interfere with loosening the anchor bolts is false. This method involves measuring the deflection or lack of contact of a machine foot when the opposite foot's bolt is loosened, using a dial indicator placed on the machine foot. The dial indicator is positioned in a way that does not obstruct access to the anchor bolts, allowing the maintenance technician to make adjustments without interference. If the dial indicator were to interfere, it would be positioned incorrectly.
Regarding the accuracy of null measurements, factors that can limit accuracy include electromagnetic interference, environmental conditions, and the quality of the connections used in the measurement setup. While a digital device might have higher sensitivity than a traditional galvanometer, it is not only the sensitivity that affects the accuracy but also the precision, resolution, and noise rejection capabilities of the device. Therefore, using a digital device that is more sensitive could improve the accuracy of null measurements if it also possesses superior characteristics in these other areas. So, the correct option is - true.