Question

a converging mirror forms a real image of height 4 cm of an object of height 1 cm placed 20 CM away from the mirror calculate the image distance and also what is the focal length of the mirror?????

Answer 1

h'= -4 cm
h= 1 cm
u= -20 cm
v=?
f=?
v/u= -h'/h
v/(-20)= -(-4)/1
v= -80 cm
1/f=1/v + 1/u
=1/(-80) + 1/(-20)
= -1/16
Therefore, f= -1/16

Answer 2

Hey there

Let me introduce to you to converging mirror :-

•Converging mirror is an spherical mirror ,

• it is also known as the concave mirror

Given :-

•Height of the image , H = - 4 cm

•Height of the object , H ₀ = 1 cm

•Distance of the object from the mirror , u = -20

•To find Image distance , v and
•Focal length , f

By using magnification formula

$\frac{height \: of \: the \: image}{height \: of \: the \: object} = \frac{ - v}{u} = > - v = \frac{ - 4 \times - 20 }{1} = - 80 cm$


{ see attached image for the further calculation }


Hence the focal length , f → -16 cm

HOPE THIS HELPS YOU ☺