This set of Surveying Multiple Choice Questions & Answers (MCQs) focuses on “Errors and Mistakes in Chaining”.
1. The length of a line measured with a 20 m chain was found to be 250 m. Calculate the true length of the line if the chain was 10 cm too long.
a) 252.25 m
b) 251.25 m
c) 225.25 m
d) 221.25 m
Explanation: Incorrect length of the chain is 20 + 10/100, ie 20.1 m. Measured length is 250, hence true length of the line is 250 ×(20.1/20)=251.25 m.
2. The length of a survey line was measured with a 20 m chain and was found to be equal to 1200 m. If the length again measured with 25 m chain it is 1212 m. On comparing the 20 m chain with the test gauge, it was found to be 1 decimeter too long. Find the actual length of 25 m chain used.
a) 22.25 m
b) 21.64 m
c) 24.25 m
d) 24. 88 m
Explanation: Incorrect length of 20 m line is 20+0.10 = 20.10 m. True length of line = 1200×(20.10/20) = 1206 m. Actual or True length of 25 m chain = (1206×25)/1212 = 24.88 m.
3. A surveyor measured the distance between two points on the plan drawn to a scale of 1 cm is equal 40 m and the result was 468 m. But, actual scale is 1 cm = 20 m. Find the true distance between the two points.
a) 992 m
b) 936 m
c) 987 m
d) 967 m
Explanation: Distance between two points measured with a scale of 1 cm to 20 m is 468/20 = 23.4 cm. Actual scale of a plan is 1 cm = 40 m. True distance between the points is 23.4 × 40 = 936 m.
4. If L is true length of chain and L’ is incorrect length of the chain the correction to area A is_________
(Where ∆L/L = e, e is small and A’ is measured area )
a) 1+2e A’
c) (1+2e) x A’
d) (1+ e)xA’
Explanation: By using A=A'(L’/L)2 and L’/L=(L+∆L)/L=1+e where e = ∆L/L.
5. If L is true length of chain and L’ is incorrect length of the chain the correction to Volume V is_______
(Where ∆L/L = e, e is small and V’ is measured area )
a) 1+3e)+ V’
d) (1+ e) ×V’
Explanation: By using V = V'(L’/L)3, e = ∆L/L and L’/L = (L+∆L)/L = 1+e. Then V = V’ (1+e)3 here e is small so V = (1+3e)xV’.
6. The difference between a measurement and the true value of the quantity measured is _____
a) True error
c) Limit of error
Explanation: The difference between a measurement and the true value of the quantity measured is the true error of the measurement. The important function of a surveyor is to secure measurements which are correct within a certain limit of error prescribed by the nature and purpose of a particular survey.
7. The difference between the two measured values of the same quantity is ______
Explanation: A discrepancy is a difference between two measured values of the same quantity. A discrepancy may be small, yet the error may be great if each of the two measurements contains an error that may be large.
8. Which of the following is not sources of errors?
Explanation: Error may arise from three sources namely instrumental, personal and natural.
9. A tape may be too long or an angle measuring instrument may be out of adjustment. Then such type of error comes under which source of error?
Explanation: Error may arise due to imperfection or faulty adjustment of the instrument with which measurement is being taken comes under an instrumental source of error.
10. Investigation of observations of various types shows that accidental errors follow a definite law. This law is called ______
a) Law of probability
b) Law of recurrence
c) Law of precise
d) Law of accuracy
Explanation: This law defines the occurrence of errors and can be expressed in the form of the equation which is used to compute the probable value or the probable precision of a quantity. This is also termed as a theory of probability.
Sanfoundry Global Education & Learning Series – Surveying.
To practice all areas of Surveying, here is complete set of 1000+ Multiple Choice Questions and Answers.