Surveying Multiple Choice Questions on “Errors in Levelling”.
1. Which of the following is not an instrumental error?
a) error due to imperfect adjustment
b) error due to sluggish bubble
c) error due to movement of objective slide
d) settlement of tripod or turning points
Answer: d
Clarification: Error due to imperfect adjustment, error due to sluggish bubble, error due to movement of the objective slide are instrumental errors. Settlement of tripod or turning points is a natural error.
2. Which of the following is a natural error?
a) error due to defective joint
b) rod not of standard length
c) variations in temperature
d) error due to sluggish bubble
Answer: c
Clarification: Error due to a defective joint, rod not of standard length, error due to sluggish bubble are instrumental errors. Variations in temperature are a natural error.
3. Which of the following is a personal error?
a) mistakes in manipulation
b) atmospheric refraction
c) settlement of tripod or turning points
d) wind vibrations
Answer: a
Clarification: Atmospheric refraction, settlement of tripod or turning points, wind vibrations are natural errors. Mistakes in manipulation is a personal error.
4. Which of the following is not a personal error?
a) mistake in rod handling
b) errors in sighting
c) mistake in reading the rod
d) error due to defective joint
Answer: d
Clarification: Mistake in rod handling, errors in sighting, a mistake in reading the rod are personal errors. Error due to the defective joint is an instrumental error.
5. Atmospheric refraction is _________
a) instrumental error
b) natural error
c) personal error
d) it’s not an error
Answer: b
Clarification: Atmospheric refraction is a natural error. Settlement of tripod or turning points, wind vibrations are also natural errors.
6. Which of the following is an instrumental error?
a) earth’s curvature
b) mistake in rod handling
c) mistakes in recording
d) error due to sluggish bubble
Answer: d
Clarification: Earth’s curvature is a natural error. Mistake in rod handling, mistakes in recording are personal errors. Error due to sluggish bubble is an instrumental error.
7. Which of the following is not a natural error?
a) error due to defective joint
b) atmospheric refraction
c) wind vibrations
d) earth’s curvature
Answer: a
Clarification: Atmospheric refraction, wind vibrations, earth’s curvature are natural errors. error due to a defective joint is an instrumental errors.
8. Which of the following is not a principle source of error in levelling?
a) instrumental error
b) natural error
c) personal error
d) Systematic error
Answer: d
Clarification: All levelling measurements are subjected to three principal source of errors. Systematic error is also called cumulative error.
9. Errors in sighting is _________
a) instrumental error
b) natural error
c) personal error
d) Systematic error
Answer: c
Clarification: Errors in sighting is a personal error. Mistakes in manipulation, mistakes in rod handling, mistakes in reading the rod etc also come under personal error.
10. Wind vibrations are natural errors.
a) True
b) False
Answer: a
Clarification: Wind vibrations is a natural error. Atmospheric refraction, settlement of tripod or turning points, wind vibrations are natural errors.
11. When distances are small which of the following error is negligible?
a) error due to defective joint
b) atmospheric refraction
c) wind vibrations
d) earth’s curvature
Answer: d
Clarification: The effect of curvature is to increase rod reading. When the distances are small the error is negligible.
12. Due to refraction, staff reading decreases.
a) True
b) False
Answer: a
Clarification: Due to refraction, the ray of light bends downwards in the form of a curve with its concavity towards the earth surface, thus decreases the staff readings.