# Surveying Questions and Answers – Triangulation – Base Line Measurement

This set of Surveying Multiple Choice Questions & Answers (MCQs) focuses on “Triangulation – Base Line Measurement”.

1. Which of the following is the most important process in the triangulation system?
a) Towers
b) Signals
c) Base line measurement
d) Reconnaissance
View Answer

Answer: c
Explanation: The base line measurement serves as an important source in the process of triangulation. It helps in determination of station points and the elevated, peak points in a terrain which help in the remaining fields like signals, towers etc.,

2. The length of the tenth base is__________
a) 1.7 miles
b) 2.7 miles
c) 4.7 miles
d) 6.7 miles
View Answer

Answer: a
Explanation: The length of the base chosen will depend upon the grade of the triangulation adopted. Generally, in India, ten bases were adopted off which the tenth base is having a length of 1.7 miles.

3. Ground which is having undulations is taken into consideration while setting base line.
a) True
b) False
View Answer

Answer: b
Explanation: In the triangulation system, base line will have the at most importance. It will be the key factor of the classification, as it describes the accuracy of the work. So in order to improve that, a ground with fewer undulations must be chosen.
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4. Which of the following is not a form of base measuring apparatus?
a) Flexible apparatus
b) Rigid bars
c) Spiral apparatus
d) Colby apparatus
View Answer

Answer: c
Explanation: The base line measurement involves certain processes of which rigid bars, flexible apparatus are the basic divisions made. The remaining will come under the sub-categories of these.

5. Corrections can be applied without measuring the temperature in field.
a) True
b) False
View Answer

Answer: a
Explanation: The measured base line can contain some errors which will decrease the accuracy of the output. While using steel and brass wires this possibility increases. So in order decrease the prone of having less accuracy, corrections are applied without considering certain parameters.
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6. Colby apparatus will come under which of the following forms?
a) Optical apparatus
b) Flexible apparatus
c) Rigid bars
d) Jaderin’s apparatus
View Answer

Answer: c
Explanation: While determining the base line, some of the methods are adopted in which usage of rigid bars is one of them. The usage of rigid bars involves in the formation of certain classes of which Colby is present.

7. Which of the following indicates a flexible apparatus?
a) Copper tape
b) Steel tape
c) Chain
d) Iron tape
View Answer

Answer: b
Explanation: A steel tape is used in case of flexible apparatus because it involves speed in the work which is an economical one. But due to speed concern, it lacks accuracy.
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8. Which of the following methods is having more amount of flexibility?
a) Flexible apparatus
b) Rigid bars
c) Colby apparatus
d) Jaderin’s method
View Answer

Answer: d
Explanation: Jaderin’s method is said to be having more flexibility when compared to the remaining methods of setting a base line. This method involves usage of tripods, tapes which are able to provide accurate value when ever used so that they won’t loose flexibility.

9. The formula for correction for temperature is ___________
a) C = α (Tm – T0) L
b) C = α (Tm – T0) + L
c) C = α (Tm + T0) L
d) C = α (Tm – T0) / L
View Answer

Answer: a
Explanation: The formula for correction of temperature can be given as C = α (Tm – T0) L, where α determines the value of coefficient of thermal expansion, Tm = mean temperature, T0 = temperature during standardisation, L = length measured.
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10. What will be the correction for absolute length of the length of the line is 20m, correction is 2m and length of the tape is 30m?
a) 1.43
b) 1.34
c) 31.42
d) 2.65
View Answer

Answer: b
Explanation: The correction for absolute length can be given as
Ca = L*c / l. On substitution, we get
Ca = 20*2 / 30
Ca = 1.34.

11. Determine the correction for the temperature, if the mean temperature is 30˚C and the temperature during standardization of tape is about 28˚C with length of the line 9m.
a) 8*10-6
b) 81*10-6
c) 18*10-6
d) 18*106
View Answer

Answer: c
Explanation: The correction for temperature can be assumed as,
Ct = α*(Tm – T0)*L. here, α = 1*10-6˚C. On substitution, we get
Ct = 1*10-6*(30-28)*9
Ct = 18*10-6.

12. Apply correction for tension, if the pull applied during measurement is 15N and standard pull is about 8N. Measured length is about 10m, cross-section of the tape is 5 sq. cm with E 2*107 N/sq. cm.
a) 7*107
b) 6*107
c) 7*1010
d) 7*102
View Answer

Answer: a
Explanation: The correction for pull or tension can be given as,
Cp = (P-Po)*L / A*E. On substitution, we get
Cp = (15-8)*10 / (5*2*107)
Cp = 7*107.

13. If the weight of the tape is 1kg having length 100m with 6 equal bays. The pull applied will be 9N, calculate the correction for sag.
a) 0.01042
b) 0.0142
c) 0.142
d) 0.00142
View Answer

Answer: d
Explanation: Correction of sag can be given as,
Cs = l*W2 / (24*n2*p2). On substitution, we get
Cs = 100*1 / (24*62*92)
Cs = 0.00142.

14. Calculate the correction for misalignment, if the length of the line is 18m with perpendicular of 3m.
a) 0.52
b) 0.25
c) 2.05
d) 5.02
View Answer

Answer: b
Explanation: The correction for misalignment can be calculated by,
Ch = d2 / 2*L. On substitution, we get
Ch = 32 / 2*18
Ch = 0.25.

15. What will be the correction for slope, if the length of the line is given as 20m with slope of 5˚46ꞌ?
a) 1.101
b) 0.011
c) 0.101
d) 1.001
View Answer

Answer: c
Explanation: The correction to slope can be given as,
Cv = 2*L*sin2(θ/2). On substitution, we get
Cv = 2*20*(5˚46ꞌ/2)
Cv = 0.101.

Sanfoundry Global Education & Learning Series – Surveying.

To practice all areas of Surveying, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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