GATE-2018 (24) :Wyllie – Time average equation

GATE

34. The scale of aerial photograph acquired from a height of 5000 m using a camera having focal length of 200 mm, is 

A) 1:5000               B)1:25000                 C)1:40000                  D) 1:60000

Solution:

Formula:

Scale = focal length (f)/ height of the camera(H)

focal length (f)= 200 mm

Heigth of the camera (H) = 5000m

                                         = 5000000 mm

Scale = 200/ 5000000

           = 1/25000

Therefore , Scale = 1: 25000