Correct Answer: it is provided with a prism to facilitate reading of its graduated circle
6. For orientation of a plane table with three points A, B and C, Bessel's drill is
Options
A. Align b through a and draw a ray towards c, align a through b and draw a ray towards c, finally align c through the point of intersection of the previously drawn rays
B. Align c through a and draw a ray towards b, align a through c and draw a ray towards b, finally align b through the point of intersection of the previously drawn rays
C. Align c through b and draw a ray towards a, align b through c and draw a ray towards a, finally align a, through the point of intersection of the previously, drawn rays
D. In the first two steps any two of the points may be used and a ray drawn towards the third point, which is sighted through the point of intersection of previously drawn rays in the final step.
Correct Answer: In the first two steps any two of the points may be used and a ray drawn towards the third point, which is sighted through the point of intersection of previously drawn rays in the final step.
7. Pick up the correct statement from the following :
Options
A. the lines of sight while observing back sight and fore sight lie in the same horizontal plane
B. the staff readings are measurements made vertically downwards from a horizontal plane
C. the horizontal plane with reference to which staff readings are taken, coincides with the level surface through the telescope axis