Surveying and Levelling

1. A back sight

1. Is always taken on a point of known elevation or can be computed
2. Is added to the known level to obtain the instrument height
3. Taken on an inverted staff is treated as negative
4. All the above

All the above

2. A bearing of a line is also known as

1. Magnetic bearing
2. True bearing
3. Azimuth
4. Reduced bearing

True bearing

3. A clinometer is used for

1. Measuring angle of slope
2. Correcting line of collimation
3. Setting out right angles
4. Defining natural features

Measuring angle of slope

4. A dumpy level is set up with its eye-piece vertically over a peg 'A'. The height from the top of peg 'A' to the centre of the eye-piece is 1.540 m and the reading on peg 'B' is 0.705 m. The level is then setup over 'B'. The height of the eye-piece above peg 'B' is 1.490 m and a reading on 'A' is 2.195 m. The difference in level between 'A' and 'B' is

1. 2.900 m
2. 3.030 m
3. 0.770 m
4. 0.785 m

0.770 m

5. A dumpy level was set up at mid-point between pegs A and B, 80 m apart and the staff readings were 1.32 and 1.56. When the level was set up at a point 10 m from A on BA produced, the staff readings obtained at A and B were 1.11 and 1.39. The correct staff reading from this set up at S should be

1. 1.435
2. 1.345
3. 1.425
4. None of these

1.345

6. A dumpy level was set up at the midpoint between two pegs A and B, 50 m apart and the staff readings at and were 1.22 and 1.06. With the level set up at 'A', the readings at 'A' and 'B' were 1.55 and 1.37. The collimation error per 100 m length of sight is

1. 0.02 m inclined upwards
2. 0.04 m inclined downwards
3. 0.04 m inclined upward
4. None of these

0.04 m inclined downwards

7. A lemniscate curve between the tangents will be transitional throughout if the polar deflection angle of its apex, is

1. ∆/2
2. ∆/3
3. ∆/4
4. ∆/6

∆/6

8. A lemniscate curve will not be transitional throughout, if its deflection angle, is

1. 45°
2. 60°
3. 90°
4. 120°

45°

9. A lens or combination of lenses in which the following defect is completely eliminated is called aplanatic

1. Spherical aberration
2. Chromatic aberration
3. Coma
4. Astigmatism