Question

In some energy meters, creeping can be avoided by __________

(a) attaching small gold pieces

(b) attaching small aluminium pieces

(c) attaching small iron pieces

(d) attaching small zinc pieces

This question was posed to me by my school principal while I was bunking the class.

Asked question is from Errors in Single Phase Energy Meters in chapter Measurement of Power and Related Parameters of Electrical Measurements

Answer 1

The correct answer is (c) attaching small iron pieces

For explanation: By attaching some iron pieces to the edge of the disc, creeping can be limited in some energy meters. Force of attraction that is experienced by the brake magnet as a result of the iron piece is enough to eliminate the creeping.