Surveying Multiple Choice Questions on “Adjustment”.
1. Which of the following is not a function of levelling head?
a) To support the main part of the instrument
b) To attach the theodolite to the tripod
c) To provide a mean for levelling the theodolite
d) To provide the exact centering over the station mark
Answer: d
Clarification: A levelling head has three distinctive functions. They are to support the main part of the instrument, to attach the theodolite to the tripod and to provide a mean for levelling the theodolite.
2. In theodolites, the upper plate carriers two plate levels placed at right angles to each other.
a) True
b) False
Answer: a
Clarification: In theodolites, the upper plate carrier’s two plate levels placed at right angles to each other. One of the plate levels is kept parallel to the trunnion axis.
3. The plate level can be centered with the help of _______
a) Focusing screw
b) Foot screw
c) Tangent screw
d) Clip screw
Answer: b
Clarification: The plate level can be centered with the help of foot screw. In some theodolites only one plate level is provided.
4. On clamping the upper screw and unclamping the lower clamp, the instrument can rotate on its outer axis without any relative motion between the two plates.
a) True
b) False
Answer: a
Clarification: On clamping the upper screw and unclamping the lower clamp, the instrument can rotate on its outer axis without any relative motion between the two plates.
5. On unclamping the upper screw and clamping the lower clamp, the instrument can rotate on its inner axis with relative motion between vernier and scale.
a) True
b) False
Answer: a
Clarification: The lower clamp is clamped and the upper clamp is unclamped, the upper plate and the instrument can rotate on the inner axis with a relative motion between the vernier and the scale.
6. Which of the following is used to test the horizontality of the transit axis or trunnion axis?
a) Levelling head
b) Levelling screw
c) Altitude bubble
d) Striding level
Answer: d
Clarification: Some theodolites are fitted with a striding level. It is used to test the horizontality of the transit axis or trunnion axis.
7. Temporary adjustments are those which are made at every instrument setting and preparatory to taking observations.
a) True
b) False
Answer: a
Clarification: Temporary adjustments are those which are made at every instrument setting and preparatory to taking observations. The temporary adjustments are setting over the station, levelling up and elimination parallax.
8. Setting up includes which of the following?
a) Centering
b) Appropriate levelling with the help of tripod legs
c) Both centering and appropriate levelling with the help of tripod legs
d) Levelling with foot screw
Answer: d
Clarification: The operation of setting up includes centering of the instrument over the station mark by a plumb Bob or by optical plummet and appropriate levelling with the help of tripod legs.
9. Parallax is a condition arising when the image formed by the object is in the plane of the cross hairs.
a) True
b) False
Answer: b
Clarification: Parallax is a condition arising when the image formed by the object is not in the plane of the cross hairs. Unless parallax is eliminated, accurate sighting is impossible.
10. Parallax can be eliminated by focusing the eye piece and objective.
a) True
b) False
Answer: a
Clarification: Parallax can be eliminated in two steps. By focusing the eyepiece for a distinct vision of the cross hairs and by focusing the objective to bring the image of the object in the plane of cross hairs.
11. For adjustment purposes, the index arm can be rotated slightly with the help of a ________ screw.
a) tangent screw
b) levelling screw
c) cliff screw
d) focusing screw
Answer: c
Clarification: For adjustment purposes, the index arm can be rotated slightly with the help of a cliff screw. It is fitted to the clipping arm at its lower end.