Write the functions of the following components of prismatic compass i) Prism, ii) Lifting pin, iii) Prism cap, iv) Agate cap

1 Answer

Answer :

i) Prism: Reading printed on horizontal face of compass ring can be read from vertical position 

ii) Lifting pin: When the instrument not in use the sight vane passes against the lifting pin which lift the needle off the pivot and holds it against a glass lid ; thus it prevents the undue wear of pivot point 

iii) Prism cap: Provided at the bottom of prism, closes window of prism when not in use 

iv) Agate cap: A small piece of hard glass provided on top of pivoted point, to reduce wear and tear of the point

Related questions

Description : State any eight component parts with its functions of prismatic compass. 

Last Answer : Component parts of prismatic compass are as follows. 1. Break pin - It is used to stop the oscillations of aluminum ring. 2. Lifting pin - It lifts the magnetic needle when sight vane is folded. ... and sighting vane when the compass is not in use to protect the compass from dirt, dust etc.

Description : Explain the temporary adjustments of prismatic compass.

Last Answer : Temporary Adjustments of Prismatic Compass 1. Fixing the compass to the tripod The compass is fixed on a tripod by rotating screw head of tripod stand. 2. Centering the compass The prismatic compass ... prism is moved using focusing stud so that readings on graduated ring will be seen clearly. 

Description : Why zero is marked at south end on a graduated circle of prismatic compass?

Last Answer : As bearing of any line is measured with respective north direction, while observing north direction, reading should be 00 0'. Therefore when object vane is bisecting north direction, at the same ... get bearings with respective north direction always, zero is marked at south end of magnetic needle.

Description : State temporary adjustments of prismatic compass

Last Answer : a) Setting the prismatic compass over prefixed survey station b) Centering the compass over nail point of station using plumb bob c) Leveling of compass in horizontal plane using level tube d) Focusing of prism by raising and lowering the focussing stud

Description : State the meaning of local attraction and state its effect on prismatic compass and how it taken care of. 

Last Answer : Local attraction: It is the deviation or deflection of magnetic needle from its normal position under influence of external magnetic forces is called as local attraction.  Effect on prismatic compass: ... compass. 3) If local attraction still persists, it is corrected by mathematical calculation. 

Description : Draw a neat sketch of prismatic compass and label its component parts

Last Answer : Sketch of prismatic compass and label its component parts

Description : Draw labeled sketch of prismatic compass.

Last Answer : Sketch of prismatic compass :

Description : State the function of reflecting mirror in prismatic compass. 

Last Answer : Function of reflecting mirror is to get image of an object located above or below the instrument level while bisection.

Description : Prismatic compass is considered more accurate than a surveyor's compass, because (A) It is provided with a better magnetic needle (B) It is provided with a sliding glass in the object vane ( ... whole circle bearings (D) It is provided with a prism to facilitate reading of its graduated circle

Last Answer : (D) It is provided with a prism to facilitate reading of its graduated circle

Description : State the functions of needle, glass cover, pivot and adjustable mirror of a compass.

Last Answer : Needle: To direct north-south direction or to give magnetic meridian. Glass cover: To prevent entry of dust in box and movement of needle due to air or wind. Pivot: To support and balance the ... it is in use. Adjustable mirror: For sighting object at high or below level of observer's eye.

Description : Write the code of signals used in ranging with respect to : i) Correct position ii) Fix the ranging rod iii) Vertical position of ranging rod iv) Move slowly to left of observer 

Last Answer : i) Correct position : Both hands above Head and then Brought Down ii) Fix the ranging rod : Both Arms extended forward horizontally and the hands depressed briskly iii) Vertical position of ranging rod : 1 ... and moved to the Left iv) Move slowly to left of observer : Slow sweeps with Left Hand

Description : Write the uses of following survey instruments i) Ranging Rod ii) Pegs iii) Cross-staff iv) Plumb bob

Last Answer : i) Ranging Rod : Ranging rod are used for ranging. ii) Pegs : Pegs are used for marking the positions of stations or terminals points of survey lines. iii) Cross-staff : It is used ... It is also used for accurate centering of the surveying instruments like theodolite, compass, plane table etc. 

Description : With neat sketch, write the procedure of measurement of fore bearing with compass.

Last Answer : For measuring fore bearing of line AB, i) Place the compass over station A, center and level it.  ii) Looking through eye slit towards object vane, bisect the ranging rod at station ... which coincides with horse hair at observer end. The observed reading is the fore bearing of line AB

Description : State the purposes of following methods of leveling. i)Profile leveling, ii)Fly leveling, iii)Check leveling iv)Reciprocal leveling

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Description : Define the terms i) Fore Bearing, ii) Open traverse, iii) Closing error, iv) Reduced bearing

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Description : Defines the terms : i) Survey Station ii) Survey Line iii)Offset iv)Triangulation 

Last Answer : i) Survey Station : It is the point on ground from which various observations are taken around it. ii) Survey Line : It is the straight line joining two successive survey stations ... iv)Triangulation : The frame work consist of number of connected well conditional triangle is called Triangulation.

Description : What are the objectives of following one each. i)Topographic Survey ii)Cadastral Survey iii)Engineering Survey iv)Mine Survey

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Description : Draw Conventional symbol for i) Embankment ii) Pond or Lake iii) Tunnel iv) Compound Wall

Last Answer : Conventional symbol for i) Embankment ii) Pond or Lake iii) Tunnel iv) Compound Wall

Description : Draw conventional symbol for: i. Cutting ii. Road with bridge iii. Orchard iv. river

Last Answer : conventional symbol for: i. Cutting ii. Road with bridge iii. Orchard iv. river

Description : Define: i) Level Line, ii) Horizontal Line, iii) Vertical Line iv) Bench Mark. 

Last Answer : j) Level Line: It is line lying in a level surface; it is therefore, normal to the plumb line at all points. ii) Horizontal Line: It is a straight line tangential to the level line at a ... RL determined with reference to the datum line. They serve as reference points for finding RL of new points. 

Description : State the uses of following instruments in survey: i)Cross staff ii) Chain iii) Pegs iv) Arrows

Last Answer : i) Cross-Staff: To set up perpendicular or right angle to given chain line OR to find foot of perpendicular from given object to a chain line. ii) Chain: Chains are used for measuring distances. iii) ... on survey lines. iv) Arrows : They are used to mark the end of each chain during chaining. 

Description : Define the following terms: (i) Level surface {ii) Datum line (iii) Reduced level (iv) Axis of telescope

Last Answer : i)Level Surface : Any surface is parallel to mean spheroidal surface of earth is said to be a level surface. The water surface of still lake is also considered to be level surface. ii) ... an imaginary line passing through the optical Centre of object glass and optical Centre of the eye piece.

Description : Find the back bearing of the following lines having fore bearing as given below: (i) PQ = N 55° 0' E (ii) EF == 280° 0' (iii) CD = S 58° 30' W (iv) OM= 180° 0'

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Description : State any four sources of errors in compass survey 

Last Answer : Following are the sources of errors in compass survey1. Instrumental survey-  a. Needle may not be perfectly straight and might not be balanced properly over the station.  b. Graduations of the rings ... substances near the station.  b. Magnetic field may vary on account of some natural causes. 

Description : State different methods of plotting compass traverse. 

Last Answer : Methods of plotting compass traverse are: 1. By parallel meridian through each station. 2. By included angle. 3. By paper protractor. 4. By rectangular co-ordinates. 5. Plotting by tangents. 6. Plotting by chords.

Description : Explain Procedure for chain and compass traversing.

Last Answer : Chain and compass traversing : 1) Reconnaissance of the area to be surveyed is done. 2) Traverse stations are fixed. 3) The F.B and B.B of the traverse are measured by prismatic compass and ... occur when the traverse is plotted. 6) This error is adjusted graphically by using Bowditch Rule'. 

Description : Enlist different errors in compass surveying.

Last Answer : Various errors in compass surveying are classified asi) Instrumental errors. ii) Personal errors or observational errors iii) Errors caused due to external errors (natural errors) i) ... magnetic declination. c) Local attraction due to proximity of magnetic substances or magnetic field.

Description : With neat sketch, explain the included angle method of plotting compass traverse. 

Last Answer : 1. Calculate all included angles of the traverse from observed bearings of the lines. e.g. <A, <B, <C, <D, <E  2. Check sum of included angles as equal to ( ... coincide with starting station (in case of closed traverse). If there is closing error, it needs to be corrected. 

Description : Describe in brief errors in compass survey.

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Description : State the principle of compass survey. 

Last Answer : The principle of compass survey is traversing, which involves a series of connected survey lines (may be open or closed) whose lengths and bearing are measured by linear and angular measuring instruments.

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Description : The zero of the graduated circle of a prismatic compass is located at  (A) North end  (B) East end  (C) South end  (D) West end 

Last Answer : (C) South end

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Last Answer : (D) An optical square

Description : In a perfect prismatic compass (A) Magnetic axis and geometric axis of the needle coincide (B) Ends of the needle and pivot are in same vertical and horizontal planes (C) Pivot is vertically over the centre of the graduated circle (D) All the above

Last Answer : (D) All the above

Description : Which one of the following statements is not correct ? (a) A surveyor's compass has two sight vanes (b) A prismatic compass has an object vane and an eye vane (c) A trough compass ... table (d) In a prismatic compass the graduations on the aluminimum disc rotate and the index remains stationary

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Description : The survey instrument used for reconnaissance survey (a) Theodelite & Dumpty level (b) Prismatic compass & Aneriod barometer* (c) All the above (d) None of them

Last Answer : (b) Prismatic compass & Aneriod barometer*

Description : Which of the instruments is not used in Reconnaissance survey. (a) Prismatic compass (b) Dumpy level * (c) Aneroid Barometer (d) Pedometer

Last Answer : (b) Dumpy level *

Description : List any eight component parts of prismatic compass with their function in brief.

Last Answer : Component parts of compass with their function. Sr.No Component Function 1 Circular metal box  To protect needle and pivot. 2 Steel pivot To carry magnetic ... prism to eye sight of observer 14 Magnetic needle To obtain the north direction. 

Description : In AT welding process what is the role of asbestos powder & slag ? (i) To separate closing pin from portion* (ii) To hold the portion (iii) Both above are correct (iv) None of the above

Last Answer : (i) To separate closing pin from portion*

Description : In AT welding process what is the role of closing pin ? (i) To hold the portion before melt (ii) To hold the asbestos powder & slag (iii) Both above are correct* (iv) None of the above

Last Answer : (iii) Both above are correct*

Description : How many grams asbestos powder is used to cover head of closing pin ? (i) 2 grams (ii) 3 grams (iii) 4 grams (iv) 5 grams*

Last Answer : (iv) 5 grams*

Description : Head of closing pin is covered with (i) Asbestos powder (ii) Slag Powder (iii) Asbestos powder than slag* (iv) None of aboveove

Last Answer : iii) Asbestos powder than slag*

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Description : Explain in brief linear measurement using : i) Pacing ii) Digital Tape 

Last Answer : i) Pacing : This method is used only for knowing approximate distance between the objects. In preliminary survey this method can be used for linear measurement. This method consists of counting the ... and compact and measures accurate reading. The maximum measuring length of digital tape is 4.8m 

Description : Define : i) Traversing ii) Magnetic Meridian

Last Answer : i) Traversing : Traversing is the series of survey lines connecting successive established traverse stations along the route of survey  ii) Magnetic Meridian : The direction indicated by ... and properly balanced Magnetic needle unaffected by local attractive force is called magnetic meridian.

Description : State the classification of surveys based on i) The nature of the field of survey. ii) The object of survey. 

Last Answer : i)The nature of the field of survey.  1.Land surveying.  2.Marine surveying or Hydrographic surveying.  3.Astronomical surveying.  ii) The object of survey. 1.Geological surveying. 2.Mine surveying. 3.Archaeological surveying. 4. Military surveying. 5. Engineeringsurveying.

Description : Define: i) Mean sea level, ii) Station point. 

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Description : Define: i) W.C.B. ii) Reduced Bearing

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