Surveying and Levelling

91. If α and β be the elevations of two objects A and B respectively, θ be the angle observed by a sextant. The correct horizontal angle is

1. cos - φ = (cos θ - sin α sin β) cos α. cos β
2. cos - φ = (sin θ - sin α sin β) cos α. cos β
3. cos - φ = (cos θ - sin α sin β) sin α. sin β
4. None of these

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92. If α is the angle between the polar ray and the tangent at the point of commencement of a lemniscate curve, the equation of the curve, is

1. l = k √sin α
2. l = k √sin 2α
3. l = k √sin 3α
4. l = k √tan 2α

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93. If 'θ' is the slope of the ground and 'l'is the measured distance, the correction is

1. 2l sin² θ/2
2. 2l cos² θ/2
3. 2l tan² θ/2
4. 2l cot² θ/2

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94. If 'θ' is the verticle angle of an inclined sight, 'δ' is the angle of the tilt of the staff, the error

1. E = 1 - [cos (θ ± δ)/cosθ]
2. E = 1 - [sin (θ ± δ)/sinθ]
3. E = 1 - [tan (θ ± δ)/tanθ]
4. None of these

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95. If +0.8% grade meets -0.7% grade and the rate of change of grade for 30 m distance is 0.05, the length of the vertical curve will be

1. 600 m
2. 700 m
3. 800 m
4. 900 m

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96. If 50 m point of a 100 m tape is 50 cm off line, and 50 m sections are straight, an error is generated equal to

1. 1/10,000
2. 1/15,000
3. 1/20,000
4. 1/25,000

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97. If a 30 m chain diverges through a perpendicular distance d from its correct alignment, the error in length, is

1. (d²/60) m
2. (d²/30) m
3. (d²/40) m
4. (d/30) m

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98. If a linear traverse follows a sharp curve round a large lake where it is difficult to have long legs, the accuracy of the traverse may be improved by

1. Taking short legs
2. Making repeated observations of angular and linear measurements
3. Making a subsidiary traverse to determine the length of a long leg
4. All the above

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99. If a tacheometer is fitted with an anal-latic lens

1. Additive constant is 100, multiplying constant is zero
2. Multiplying constant is 100, additive constant is zero
3. Both multiplying and additive constants are 100
4. Both multiplying and additive constants are 50

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100. If arithmetic sum of latitudes of a closed traverse is '∑L' and closing error in latitude is 'dx', the correction for a side whose latitude is 'l', as given by Transit Rule, is

1. l × (dx/∑ lar)
2. l × (∑ Lat/dx)
3. ∑ Lat × (dx/l)
4. None of these

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