Surveying and Levelling

11. A relatively fixed point of known elevation above datum, is called

1. Bench mark
2. Datum point
3. Reduced level
4. Reference point

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12. A series of closely spaced contour lines represents a

1. Steep slope
2. Gentle slope
3. Uniform slope
4. Plane surface

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13. A sewer is laid from a manhole 'A' to a manhole 'B', 250 m away along a gradient of 1 in 125. If the reduced level of the invert at 'A' is 205.75 m and the height of the boning rod is 3 m, the reduced level of the sight rail at 'B', is

1. 208.75 m
2. 202.75 m
3. 206.75 m
4. 211.75 m

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14. A standard steel tape of length 30 m and cross-section 15 × 1.0 mm was standardised at 25°C and at 30 kg pull. While measuring a base line at the same temperature, the pull applied was 40 kg. If the modulus of elasticity of steel tape is 2.2 × 106 kg/cm², the correction to be applied is

1. - 0.000909 m
2. + 0.0909 m
3. 0.000909 m
4. None of these

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15. A tape of length 'l' and weight 'W' kg/m is suspended at its ends with a pull of 'P'kg, the sag correction is

1. l³W²/24P²
2. l²W³/24P²
3. l²W²/24P³
4. lW²/24P

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16. A theodolite is said to be in perfect adjustment if

1. Rotation axis is vertical to the transit axis
2. Transit axis is perpendicular to line of collimation
3. Line of collimation sweeps out a vertical plane while the telescope is elevated or depressed
4. All the above

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17. A transit is oriented by setting its vernier A to read the back azimuth of the preceding line. A back sight on the preceding transit station taken and transit is rotated about its vertical axis. The vernier A reads

1. Azimuth of the forward line
2. Bearing of the forward line
3. Back bearing of the forward line
4. Equal to 360°-azimuth of the forward line

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18. A traverse deflection angle is

1. Less than 90°
2. More than 90° but less than 180°
3. The difference between the included angle and 180°
4. The difference between 360° and the included angle

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19. A uniform slope was measured by the method of stepping. If the difference in level between two points is 1.8 m and the slope distance between them is 15 m, the error is approximately equal to

1. Cumulative, + 0.11 m
2. Compensating, ± 0.11 m
3. Cumulative, - 0.11 m
4. None of these

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20. A well conditioned triangle has no angle less than

1. 20°
2. 30°
3. 45°
4. 60°

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