Question

a convex mirror has a focal length of 20 centimetre find the position of the object for which the image will be half the size of the object

Answer 1

please search on Google

Answer 2

h2= h1/h2,u=? M = h2/h1 = -v/u = 1/2

v= o/2 1/v+1/u = 1/f

1/-u/2+1/u =1/f
1/u (1-2) =1/f -1/u = 1/f
u = f = -18 cm