Question

How large will an image be formed of an artificial satellite, 5m in diameter, passing at an altitude of 500 km if it is photographed by a camera with a lens of focal length 10 cm.

• A. ${10}^{-2}m$
• B. ${10}^{-4}m$
• C. ${10}^{-6}m$
• D. $5\times {10}^{-6}m$

Answer 1

Answer: (C)

${10}^{-6}m$

$m=\frac{v}{u}=\frac{I}{O}=\frac{f}{u}$

$\therefore \frac{I}{5}=\frac{10\times {10}^{-2}}{500\times {10}^3}$

$\Rightarrow I={10}^{-6}m$