Question

a concave mirror forms an image of 2 cm high object on a screen placee 5cm away from mirror.the height of image is 50 cm find focal length and distance between mirror and object​

Answer 1

the image formed is of the same size and inverted,

therefore the magnification must be - 1 .

the magnification = image distance divided by object distance = v /u

if m=-1 then the object distance = -(image distance)

the relation ship between image distance (v) , object distance(u) and focal length is

1 /v + 1/u = 1/f

where f is the focal length of the mirror.

if v = u then 2 / u = 1/f

or u = 2.f = 40 cm

so the object must be placed at the centre of curvature as 2.f = R = radius of curvature.