This set of Surveying Multiple Choice Questions & Answers (MCQs) focuses on “The Prismoidal Correction”.
1. Correction applied in prismoidal correction is always__________
Explanation: The formula used while calculating volume needs to apply certain correction so as to reduce the error occurred. In the case of prismoidal correction, the correction applied will be always subtractive, which means it should be subtracted from the volume obtained.
2. The calculation of mid-area is necessary in case of prismoidal correction.
Explanation: Mid-area calculations were generally carried out in case of calculation of volume by trapezoidal formula. In case of prismoidal corrections, the mid-area is used for deriving its formula.
3. Which of the following value is necessary in case of determining the correction in prismoid?
d) Distance between the sides
Explanation: The prismoidal correction requires certain values which can be applied for determining the corrections in both prismoid and trapezoid. The value of the equidistant position of the prisms must be known for further continuation problem.
4. Prismoidal correction can be given as________
a) Addition between the volume calculated and that obtained from the prismoid formula
b) Summation between the volume calculated and that obtained from the prismoid formula
c) Difference between the volume calculated and that obtained from the prismoid formula
d) Product between the volume calculated and that obtained from the prismoid formula
Explanation: Prismoidal correction can be given as the difference between the volume calculated and that obtained from the prismoid formula. The obtained correction is always subtractive.
5. Prismoidal correction is obtained from which of the following formulae?
a) Prismoid formula
b) Trapezoidal formula
c) Square formula
d) Rectangular formula
Explanation: It is evident that the formula for prismoidal correction can be obtained from the prismoidal formula. But the usage can be done in both prisomidal and trapezoidal formulae because it involves only correction.
6. Find the prismoidal correction, if the area of cross sections were given as 114.65 sq. m and 56.76 sq. m, which are 2 m distant apart having 3 sides.
Explanation: The value of correction for prismoid can be given as
Cp = d n(h-h1)2/6. On substitution, we get
Cp = 2*3(114.65-56.76)2/6
Cp = 3351.25.
7. If the areas of cross sections of one side area given as 117.86 sq. m, 105.76 sq. m and the other side as 98.76 sq. m, 86.54 sq. m. the values of b, n, m, mꞌ and d are given as 2, 3, 4,4 and 1 respectively. Find the correction of prismoid in case of side hill section.
Explanation: The formula for the correction of prismoid in case of side hill section can be given as
Cp = d (w-w1)*(b/2 – b/2 + m*h – mꞌ*hꞌ)/12*n. On substitution, we get
Cp = 1 (117.86-98.76) * (4*105.76 – 4*86.54) / 12*3
Cp = 30.6.
8. Prismoidal correction can be applied to which of the following formulae?
a) Rectangular formula
b) Square formula
c) Trapezoidal formula
d) Quadrilateral formula
Explanation: Trapezoidal formula uses the prismoidal correction to reduce the error caused. The impact of the error must be reduced for having a better output. The formula derived for prismoidal correction is having similar conditions as of trapezoidal formula.
9. Find the correction applied for two-level section if area of cross sections at different sides were given as 115.31, 165.72 and 65.87, 54.23,which unit distant apart having number of sides 2.
Explanation: The formula for correction of two-level section can be given as
Cp = d*(w-wꞌ)*(w1-w1ꞌ) / 6*n. on substitution,
We get Cp = 1 (115.31-65.87)*(165.72-54.23) / 6*2 = 459.33.
10. What will be the correction for three level sections, if the areas of 3 different sides, which are having unit distance are 121.31 sq. m, 145.76 sq. m, 176.65 sq. m and 45.87 sq. m, 45.67 sq. m, 72.43 sq. m?
Explanation: The formula of correction for three level section can be given as
Cp = d*(h-hꞌ)*(w-wꞌ+w1-w1ꞌ) / 12. On substitution, we get
Cp = 1*(121.31-45.87)*(145.76-45.67 +176.65-72.43) / 12
Cp = -25.96.
Sanfoundry Global Education & Learning Series – Surveying.
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