Question

. An object O stands on the central axis of a spherical, concave mirror. The object distance is

do = 14.0 cm and the radius of curvature of the mirror is 18.0 cm.

a) Use ray tracing to sketch the size and location of the image.

b) Including the sign, what is the image distance di?

c) Including the sign, what is the magnification?

d) Is the image real or virtual? Explain.

Answer 1

For a concave mirror object is placed in front of the mirror,Radius of curvature f=R/2.From mirror formula 1/f=1/u+1/v we can find image distance. Given data: Object distance do=14cm,radius of curvature R=18cm. From the formula f=R/2=18/2=9cm. So clearly the object is placed between focus and radius of curvature of the mirror,then the image must be formed beyond C.

(a)

(b)1/f=1/do+1/di

1/9=1/14+1/di

1/di=1/9-1/14=5/14*9

di=25.2cm this is image distance and it is negative(-ve)

(c) Magnification m=-di/du=-25.2/14=-1.8

(d) Clearly the object is placed between focus and radius of curvature,the image is formed beyond 'C'. The image formed is Real,inverted and enlarged.