While viewing through a level telescope and moving the eye slightly, a relative movement occurs between the image of the levelling staff and the cross hairs. The instrument is
A. correctly focussed
B. not correctly focussed
C. said to have parallax
D. free from parallax
ans. c
A. correctly focussed
B. not correctly focussed
C. said to have parallax
D. free from parallax
ans. c
No comments:
Post a Comment