Q. 84.1( 7 Votes )
How can we find the (rough) focal length of a concave mirror?
Method We can put the object far away from the concave mirror and place the screen where the image is formed. The place where the image formed is sharpest is the focus of the mirror, measure the distance between the focus and mirror to get the focal length.
Explanation When an object is kept at the infinity than the image is formed at the focus of the concave mirror.
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