Question

A concave mirror of focal length f produces a real image ,which is'n' times the size of the object . Calculate the distance of the object from the mirror

Answer 1

According to your question :-
m = h'/h = n

also ,

since ,

m = f /f-u

n = f/f-u

-u = f/n - f

-u = f(1-n) /n

u = -f(1-n) / n