Question

an object is held at 40cm from a concave mirror of focal length 60cm what is the distance of the image from the mirror?​

Answer 1

Answer:

let's object U and the distance of image is V and focal lenth F

Explanation:U=(-)40

                      V=x

                       F=(-)60

now put it directly in formula 1/v+1/u=1/f

                                   1/v+1/(-40)=1/(-60)

                                    =(+)120

                         behind the mirror

     

Answer 2

Given :-

Object distance (u) = -40cm

Focal length (f) = -60cm

Image distance (v) = ?

Solution :-

Mirror formula :- 1/v + 1/u = 1/f

Or,

1/v = 1/u - 1/f

1/v = 1/(-40) - 1/(-60)

1/v = - 1/40 + 1/60

1/v = (-60 + 40)/2400

1/v = -20/2400

1/v = -2/240

1/v = -1/120

v = -120cm

•°• Image is formed at a distance of 120cm in front of the mirror.

- The image is real and inverted.

Other formulas :-

Lens formula :- 1/v - 1/u = 1/f

Magnification of mirror :- -v/u

Magnification of lens :- v/u