Answer :
Final answer:
A dial indicator is the correct tool for measuring rotor shaft alignment or disk rotation planes, as it is designed to measure small distances and angles with precision.
Explanation:
The correct tool for measuring the alignment of a rotor shaft or the plane of rotation of a disk is a dial indicator. A dial indicator is specifically designed to measure small distances or angles, making it ideal for checking the precision of rotating components in machinery.
Feeler gauges are used to measure gap widths, protractors measure angles, and micrometers measure small distances with high precision but are not suited for checking the alignment of rotating parts.
