Question

an object 2cm high is placed 10 cm in front of a mirror. what type of mirror and what radius of curvature needed for an upright image that is 4 cm high
answer(40cm)
plz give me a solution

Answer 1

h=2cm  u=10cm h'=4cm
since the image is upright it mans that the image is a virtual image.
 magnification for a mirror  is given by m=-v/u
m=-(40/-10)
so the magnification is +4
it means that the image is virtual erect and enlarged.
concave mirror can give a virtual erect and an enlarged image.
in order to find the radius of curvature we have to find the focal length of the mirror.
focal length is given by 1/f=1/u+1/v
1/f=1/-10 +1/40
1/f= -40+10/10*40
 f= 13.33cm
 radius of curvature =2*focal length   =26.66cm
 (the answer given by you as 40 cm is wrong)