The length from pin hole to where object is formed is actually the focal length f, (the size of pin hole camera)
f=u/(1+m)
Where u is object distance and m is magnification.
Magnification is the ratio of height of object and height of object
= 5/5=1.
Therefore f= 25/(1+1)= 12.5 cm
Nolana answered the question on March 22, 2019 at 10:18
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