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

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

1 Answer

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 magnetic needle when it is in use.

Adjustable mirror: For sighting object at high or below level of observer’s eye.
by

Related questions

State the function of reflecting mirror in 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.

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

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.

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

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

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

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

Last 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 ... piece of hard glass provided on top of pivoted point, to reduce wear and tear of the point

State temporary adjustments of prismatic compass

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

State any four sources of errors in compass survey

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. 

State different methods of plotting compass traverse.

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.

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

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. 

State the principle of compass survey.

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.

Explain the temporary adjustments of prismatic compass.

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. 

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

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.

Explain Procedure for chain and compass traversing.

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'. 

Enlist different errors in compass surveying.

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.

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

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. 

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

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

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

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

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

Describe in brief errors in compass survey.

Description : Describe in brief errors in compass survey.

Last Answer : Errors in Compass Surveying. The errors are classified as: 1. Instrumental errors. 2. Personal or Observational errors. 3. Errors due to External Influences (Natural errors etc.).  (1 ... in magnetic declination. (iii) Local attraction due to proximity of electric lines, steel structures etc.

Draw labeled sketch of prismatic compass.

Description : Draw labeled sketch of prismatic compass.

Last Answer : Sketch of prismatic compass :

Define Dip and deflection of needle.

Description : Define Dip and deflection of needle.

Last Answer : Dip of the magnetic needle: It is the upward or downward movement of magnetic needle in vertical plane due to earth's gravitational force is known as dip of needle. Deflection of needle : ... west direction, that horizontal angle between magnetic and true north is said to be declination of needle.

Explain dip of magnetic needle with neat sketch.

Description : Explain dip of magnetic needle with neat sketch. 

Last Answer : i) The inclination of the magnetic needle with the horizontal is called as magnetic dip of the needle. ii) Ordinary needle if perfectly balanced on pivot, remains in horizontal position. But when the needle ... sliding weight is attached on the side of the needle which is at higher position.  

Explain ‘Declination of Magnetic needle’ and types of declination.

Description : Explain ‘Declination of Magnetic needle’ and types of declination. 

Last Answer : Ans: The magnetic meridian at a place does not coincide with the true meridian at that place. The horizontal angle made by the magnetic meridian with the true meridian is called magnetic declination'. ... in others it points to the west of the true meridian called as West declination'

Define the terms - dip of needle, magnetic bearing, fore bearing and back bearing.

Description : Define the terms - dip of needle, magnetic bearing, fore bearing and back bearing.

Last Answer : Dip of needle: It is downward inclination or small angle made by freely suspended magnetic needle with the horizontal. Magnetic bearing: Magnetic bearing of a survey line is the horizontal angle ... of line measured in backward direction or opposite direction of survey, is known as back bearing.

Explain the terms magnetic declination and dip of needle.

Description : Explain the terms magnetic declination and dip of needle.

Last Answer : Magnetic Declination: The horizontal angle between the magnetic meridian and true meridian is known as magnetic declination. When the north end of magnetic needle is pointed towards west side of ... needle is deflected downwards and southern hemisphere south end of the needle is deflected downwards.

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 (C) Its graduations are in whole circle bearings (D) It is provided with a prism to facilitate reading of its graduated circle

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

Which of the following is an antifriction bearing? (a) journal bearing (b) collar bearing (c) needle bearing (d) pivot bearing

Description : Which of the following is an antifriction bearing? (a) journal bearing (b) collar bearing (c) needle bearing (d) pivot bearing

Last Answer : (c) needle bearing

The magnetic meridian at any point, is the direction indicated by a freely suspended (A) Magnetic needle (B) And properly balanced magnetic needle (C) Properly balanced and uninfluenced by local attractive force (D) Magnetic needle over an iron pivot

Description : The magnetic meridian at any point, is the direction indicated by a freely suspended (A) Magnetic needle (B) And properly balanced magnetic needle (C) Properly balanced and uninfluenced by local attractive force (D) Magnetic needle over an iron pivot

Last Answer : (C) Properly balanced and uninfluenced by local attractive force

The vertical angle between longitudinal axis of a freely suspended magnetic needle and a horizontal line at its pivot, is known (A) Declination (B) Azimuth (C) Dip (D) Bearing

Description : The vertical angle between longitudinal axis of a freely suspended magnetic needle and a horizontal line at its pivot, is known (A) Declination (B) Azimuth (C) Dip (D) Bearing

Last Answer : (C) Dip

1. Why does a compass needle get deflected when brought near a bar magnet? -Physics-10

Description : 1. Why does a compass needle get deflected when brought near a bar magnet? -Physics-10

Last Answer : The compass needle is a small magnet. When the compass needle is brought close to a bar magnet, the magnetic field lines of the compass needle interact with the magnetic field lines of bar magnet, which causes the compass needle to deflect.

If Veronica spins in a circle with the compass in her hand which force keeps the compass' needle pointing north?

Description : If Veronica spins in a circle with the compass in her hand which force keeps the compass' needle pointing north?

Last Answer : Magnetic Force

The needle of a magnetic compass is generally supported on a (a) Bush bearing (b) Ball bearing (c) Needle bearing (d) Jewel bearing

Description : The needle of a magnetic compass is generally supported on a (a) Bush bearing (b) Ball bearing (c) Needle bearing (d) Jewel bearing

Last Answer : (c) Needle bearing

A compass is located at the geographical North Pole. In which direction would its needle point?

Description : A compass is located at the geographical North Pole. In which direction would its needle point?

Last Answer : To the magnetic north pole.

How does the magnetic compass needle behave in a magnetic field ?

Last Answer : It assures a position which follows a line of magnetic flux

State the fundamental axes and mention their relationship for a dumpy level.

Description : State the fundamental axes and mention their relationship for a dumpy level.

Last Answer : Fundamental axis of dumpy level are as follows; i) The vertical axis ii) The axis of bubble tube iii) The line of collimation iv) The axis of the telescope Relationship between ... iii) Axis of telescope and line of collimation should coincide when dumpy level is correctly leveled.

State the situation where plane table is suitable.

Description : State the situation where plane table is suitable. 

Last Answer : 1) It is most suitable for preparing small scale maps 2) It is suitable in magnetic are where compass survey is not reliable 3) It is most suitable for filling in details between stations fixed by triangulation 4) It is suitable where accuracy is not required.

State the two uses of survey based on geodetic surveying

Description : State the two uses of survey based on geodetic surveying

Last Answer : Two uses of survey based on geodetic surveying:- i) To determine the precise position s on the surface of the earth. ii) Preparation of maps of large area like map of a country, state ... ) Establishment of GTS bench Marks across the country. iv) Preparation of military maps for defense purposes.

State the important points kept in mind while recording the staff readings in level pages with respect first reading, intermediate reading, last reading, change point, carry forward from one page to next page-Remark

Description : State the important points kept in mind while recording the staff readings in level pages with respect first reading, intermediate reading, last reading, change point, carry forward from one page to next page-Remark

Last Answer : 1) First reading is on bench mark point and should be noted in back sight(BS) column 2) Intermediate reading (IS) should be taken on the points between first and last station. 3) Last reading ... column of next page 6) Remark column should have denote First and Last RL along with change points.

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

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

Last Answer : 1. Profile leveling- To determine the undulation of ground surface along given line for alignment of road, canal or pipe, railway line 2. Fly leveling-It is used to for connecting B.M. to ... is used to find the difference in leveling between two points two point obstructed due to river or pond.

State fundamental lines and their relationships with each other of dumpy level.

Description : State fundamental lines and their relationships with each other of dumpy level.

Last Answer : Fundamental axes of dumpy level : i) The vertical axis ii) The axis of bubble tube iii) The line of collimation iv) The axis of the telescope Relations of Fundamental axes : i) The ... to the axis of the bubble tube. iii) Axis of telescope and line of collimation should coincide.

State advantages of plane table survey one each with respect to booking and suitability

Description : State advantages of plane table survey one each with respect to booking and suitability

Last Answer : Booking of observations: i) Field work and plotting work done simultaneously ii) ) Notes of measurement are seldom required and possibility of mistakes in booking is eliminated. Suitability of PT ... and work where great accuracy is not required. ii) Mostly suitable for survey in plain terrain

State two advantages of telescopic alidade over simple alidade.

Description : State two advantages of telescopic alidade over simple alidade.

Last Answer : Advantages of telescopic alidade : i) Telescopic alidade is more accurate in bisection than simple alidade ii) Telescopic alidade is useful in comparatively longer range objects. iii) It can be easily ... is not possible by simple alidade. iv) It gives quicker bisection which saves time ultimately.

Define orientation. State two methods of orientation. Which method is most accurate and why?

Description : Define orientation. State two methods of orientation. Which method is most accurate and why? 

Last Answer : Orientation is the process of keeping plane table in same position as that is occupied in previous station. Methods of orientation: i) Magnetic meridian method using trough compass ii) Back ... and not by using trough compass. Therefore there is no error occurring due to local attraction.

State four instruments used for setting offsets.

Description : State four instruments used for setting offsets.

Last Answer : i) Instruments used for setting offsets: 1)Chain 2)Tape 3) Open & French Cross Staff 4) Circular & Indian Optical Square  ii) Principle of optical square: The angle between the first incident ray and the last reflected ray is twice to that of angle between two mirrors in optical square.

Define local attraction. State two causes of local attraction.

Description : Define local attraction. State two causes of local attraction.

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. Causes of local attraction : 1. Iron ... structure 2. Electric cable line 3. High voltage current 4. Bunch of key 5. Steel Tape 

What is bench mark? State the types of bench mark and explain any one type.

Description : What is bench mark? State the types of bench mark and explain any one type.

Last Answer : Bench Mark- It is fixed reference point of known or assumed elevation. Types of bench mark1. Great trignometrical survey bench mark 2. Permanent bench mark 3. Arbitrary bench mark 4. Temporary bench ... Karachi are given in catalogue formed by department. They are also known as G.T.S. Bench mark

Describe quadrantal bearing system. State the purpose it is used.

Description : Describe quadrantal bearing system. State the purpose it is used. 

Last Answer : Quadrantal Bearing - 1. The magnetic bearing of line measured clockwise or anticlockwise from north or south pole whichever is nearer. 2. These bearings are also called as reduced bearings. 3. ... lines in a closed traverse. 2. It is used to calculate back bearing for respective quadrants.

State and describe the types of offsets.

Description : State and describe the types of offsets. 

Last Answer : 1. Perpendicular offset- When the offset is taken at 900 to the survey line, then it is known as perpendicular offset. 2. Oblique offset- When the offset is taken at an angle other than 900 ( ... when offset is set by swinging chain or tape to survey line, such formed offset is called Swing offset.

State any two uses of survey.

Description : State any two uses of survey.

Last Answer : Survey is useful for following: 1. To prepare a map or plan of the surveyed area for attaching it to legal documents. 2. To plot control points of boundries of locality 3. To determine ... . 5. To decide suitable gradient and camber of road depending on equal volume of cutting and filling.

What is meant by local attraction? How will you suspect local attraction at the field ? state its effect on included angle.

Description : What is meant by local attraction? How will you suspect local attraction at the field ? state its effect on included angle.

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. Suspect of local attraction ... The needle is affected by local attraction therefore it does not give a corrected angle

State fundamental axis of dumpy level and give their relationship

Description : State fundamental axis of dumpy level and give their relationship 

Last Answer : Fundamental axes of dumpy level : i) The vertical axis ii) The axis of bubble tube iii) The line of collimation iv) The axis of the telescope Relations of Fundamental axes : i) The ... parallel to the axis of the bubble tube. iii) Axis of telescope and line of collimation should coincide. 

State the use of following- 1. Arrow 2. Wooden peg

Description : State the use of following- 1. Arrow 2. Wooden peg

Last Answer : 1. Arrow Arrows are used for counting the number of chains while measuring a chain line. 2. Wooden peg Pegs are used for fixing the instrument station on the ground permanent marking