Physics, asked by shiva4701, 1 year ago

Define the following terms: Line of collimation, Level surface.

Answers

Answered by mbasil22
1

Line of Collimation:

Line joining the intersection of the cross-hairs to the optical center of the objective and its continuation. It is also know as Line of sight. Line of sight : is defined as the intersection of the cross hairs and the optical centre of the objective lens.

Level Surface:

A small exploration of the connection between the gradient vector and level surfaces. For a function f, the gradient vector grad f has the properties that. it points in the direction in which f increases the fastest, and. it is perpendicular to level curves or surfaces of f.



Answered by sree4sreejith
1
R.L. (Reduced Level) : The R.L. of any point represents its elevation (above or below0 with respect to mean sea level as datum.

Axis of telescope : line joining the optical center of the objective to the center of the eyepiece.

Axis of level tube : an imaginary line tangential to the longitudinal curve of the tube at its mid-point.

Back sight : Staff reading taken on a point of known elevation.

Bench Mark : A fixed point of known elevation above the datum .

Datum : The level surface (real or imaginary) used for reference is called a datum.

Elevation : of a point/ station, on or near the surface of the earth, is its vertical distance above or below a datum .

Height of instrument : Elevation of the line of sight of the telescope.

Horizontal plane : a plane always perpendicular to one considered plumb line. It is tangent to a level surface.

Horizontal line : is a line always perpendicular to one considered plumb line. It is tangent to a level line. It lies in Horizontal plane.

Horizontal distance : In plane surveying, distance measured along a level line termed as horizontal distance.

Intermediate sight : Staff reading on a point, other than back sight and fore sight, of whose elevation is to be determined.

Level surface : A level surface is an equipotential surface of the earth's gravity field. It is a curved surface and every element of which is perpendicular to plumb line. A body of still water provides the best example of a level surface.

Level line : is a curved line normal to plumb lines at all points. Thus, it lies in a level surface.

Line of collimation : Line joining the intersection of the cross-hairs to the optical center of the objective and its continuation. It is also know as Line of sight.

Line of sight : is defined as the intersection of the cross hairs and the optical centre of the objective lens.

Mean Sea level : Mean sea level (MSL) at a location is obtained by averaging the height of the surface of the sea for all stages of the tides for a period of 18.6 years. It is used as a vertical datum level surface. For India , MSL of Mumbai port is considered as reference surface for finding vertical height.

Plumb line : is the direction of the lines of force of earth's gravity field. In plane surveying, it is defined by the direction of a freely suspended plumb-bob.

Relative elevation : Difference in elevation between two points is the vertical distance between the level lines passing through the points.

Turning point : is an intermittent/ intervening point between set up of stations at which both fore sight and back sight readings are taken.

Vertical plane : is a plane along a plumb line. It is tangent to a Horizontal plane

Vertical line : is a line along a plumb line. It is tangent to a Horizontal line . It lies in Vertical plane.

Vertical distance : is the distance measured along a plumb line .

Vertical angle : is an angle between two intersecting straight lines in a vertical plane .

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