![A square area (on the surface of the earth) with side 100 m and uniform height, appears as 1 cm2 on a vertical aerial photograph](https://www.gkseries.com/blog/wp-content/uploads/2023/09/A-square-area-on-the-surface-of-the-earth-with-side-100-m-and-uniform-height-appears-as-1-cm2-on-a-vertical-aerial-photograph.jpg)
Q. A square area (on the surface of the earth) with side 100 m and uniform height, appears as 1 cm2 on a vertical aerial photograph. The topographic map shows that a contour of 650 m passes through the area. If focal length of the camera lens is 150 mm, the height from which the aerial photograph was taken, is
(A) 800 m (B) 1500 m (C) 2150 m (D) 3150 m
Ans: 2150 m
Sol:
Actual area = 100×100=104m2
Area on the map = 1 cm2 = 10−4 m2
Elevation of the surface = 650 m
The focal length of the camera, f = 150 mm
Scale of the photograph,
![](https://www.gkseries.com/blog/wp-content/uploads/2023/09/Screenshot-916.png)