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A concave mirror of focal length `f` produces a real image `n` times the size of the object. What is the distance of the object from the mirror? |
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Answer» Since image is real, magnification `m` is `-ve`. Let distance of object from pole is `x`. `u=-x,m=-n,f=-f` `m=-(v)/(u)implies-n=(v)/(-x)` `v=-nx` `(1)/(v)+(1)/(u)=(1)/(f)` `(1)/(-nx)+(1)/(-x)=(1)/(-f)implies(1)/(nx)+(1)/(x)=(1)/(f)` `(1+n)/(nx)=(1)/(f)impliesx=((n+1)f)/(n)` |
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