1. Parallax is a condition arising when the image formed by the object is in the plane of the cross hairs.
a) true
b) false
Explanation: 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.
2. Parallax can be eliminated by focusing the eye piece and objective.
a) true
b) false
Explanation: 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.
3. 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
Explanation: 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.
4. To measure the horizontal angle which of the following is the first step?
a) Releasing all clamps
b) Levelling instrument
c) Turning plates
d) Clamping the plates
Explanation: To measure the horizontal angle, firstly we set up instrument and level it. Secondly, releases all clamps. Turning the upper and lower plates in opposite directions till the zero of the one of the vernier is against the zero of the scale. Next clamp the plates together by upper clamp and lower clamp and bring the two zeros into exact coincidence by turning upper tangent screw. It continues next procedure.
5. After setting up the instrument first thing done by the surveyor is _________
a) releasing all clamps
b) levelling instrument
c) turning plates
d) clamping the plates
Explanation: Firstly, we set up an instrument and level it. Secondly, releases all clamps.
6. The method of repetition is used to measure a horizontal angle to a finer degree of accuracy than that obtained with the least count of the vernier.
a) true
b) false
Explanation: In this method of repetition, angle is measured two or more times by allowing the vernier to remain clamped each time at the end of each measurement. Instead of setting it back at zero when sighting at previous station.
7. To measure a horizontal angle, after releasing all clamps, we turn the upper and lower plates in the same direction.
a) True
b) false
Explanation: After releasing all clamps. Turning the upper and lower plates in opposite directions till the zero of the one of the vernier is against the zero of the scale.
8. After levelling of an instrument is done what is the next up?
a) Releasing all clamps
b) Loosing the lower clamp
c) Turning plates
d) Clamping the plates
Explanation: To measure the horizontal angle, firstly we set up instrument and level it. Secondly, releases all clamps.
9. To measure a horizontal angle by direct method is also called a repetition method.
a) true
b) false
Explanation: To measure a horizontal angle by direct method is also called the reiteration method. It is suitable for measurements of angles of a group having a common vertex point.
10. If one of the vernier is at 0° then another vernier reading shows / also shows ______
a) 90°
b) 0°
c) 180°
d) 45°
Explanation: Turning the upper and lower plates in opposite directions till the zero of the one of the vernier is against the zero of the scale. Next clamp the plates together by upper clamp and lower clamp and bring the two zeros into exact coincidence by turning upper tangent screw. Now when we take reading on another vernier it should be 180°, if there is no instrument error.