If the needle of a compass is sluggish, then the type of error will be
- AInstrumental errorCorrect
- BPersonal error
- CNatural error
- DNone of the above
Solution
Concept
Classification of errors: instrumental, personal and natural
Step-by-step solution
1. A sluggish needle is a defect of the instrument itself. 2. Errors due to defects in the instrument are instrumental errors.
Explanation
A sluggish magnetic needle (caused by a blunt pivot or weak magnetism) does not settle in the magnetic meridian properly. It is a fault of the instrument, so the error is instrumental.
Shortcut
Instrument fault → instrumental; observer fault → personal; weather/site → natural.
Common mistake
Choosing natural because the needle is affected by magnetism.
Correct answer: A) Instrumental error