
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,
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