Question:
A road section of length \(1\) km scales \(8\) cm on a vertical photograph. The focal length of the camera is \(160\) mm. If the terrain is fairly level, then the flying height will be
A road section of length \(1\) km scales \(8\) cm on a vertical photograph. The focal length of the camera is \(160\) mm. If the terrain is fairly level, then the flying height will be
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For vertical aerial photographs,
\[
\boxed{
\text{Scale}=\frac{f}{H}
}
\]
Ensure that focal length and flying height are expressed in the same units.
Updated On: Jul 23, 2026
- \(20\) m
- \(2000\) m
- \(20\) km
- \(200\) km
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The Correct Option is B
Solution and Explanation
Concept:
For a vertical aerial photograph,
\[
\boxed{
\text{Scale}=\frac{f}{H}
}
\]
where
\[
f=\text{Focal length},
\]
\[
H=\text{Flying height above ground}.
\]
Also,
\[
\text{Scale}
=
\frac{\text{Photo length}}{\text{Ground length}}.
\]
Step 1: Calculate the photo scale. Ground length \[ 1\text{ km}=100000\text{ cm} \] Photo length \[ 8\text{ cm} \] Hence, \[ \text{Scale} = \frac{8}{100000} = \frac{1}{12500} \]
Step 2: Calculate the flying height. Given, \[ f=160\text{ mm}=0.16\text{ m} \] Using \[ \frac{f}{H} = \frac{1}{12500}, \] \[ H = 0.16\times12500 = 2000\text{ m} \] Thus, \[ \boxed{H=2000\text{ m}} \] Therefore, the correct option is \[ \boxed{(B)\;2000\text{ m}.} \]
Step 1: Calculate the photo scale. Ground length \[ 1\text{ km}=100000\text{ cm} \] Photo length \[ 8\text{ cm} \] Hence, \[ \text{Scale} = \frac{8}{100000} = \frac{1}{12500} \]
Step 2: Calculate the flying height. Given, \[ f=160\text{ mm}=0.16\text{ m} \] Using \[ \frac{f}{H} = \frac{1}{12500}, \] \[ H = 0.16\times12500 = 2000\text{ m} \] Thus, \[ \boxed{H=2000\text{ m}} \] Therefore, the correct option is \[ \boxed{(B)\;2000\text{ m}.} \]
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