Surveying
The foot of the perpendicular on the picture plane through the optical centre of the camera lens, is known as

Isocenter
Principal point
Perspective centre
Plumb line

ANSWER DOWNLOAD EXAMIANS APP

Surveying
Refraction correction

has no effect on curvature correction
partially eliminates curvature correction
adds to the curvature correction
completely eliminates curvature correction

ANSWER DOWNLOAD EXAMIANS APP