Answer:
9.52 cm
Explanation:
Height of tree that is height of object O =3.40 cm
Height of image that is I =1.60 cm
We know that magnification [tex]m=\frac{hieght\ of\ image}{height\ of\ object}=\frac{-1.60}{3.40}=-0.47[/tex] negative sign for the inverted image
We also know that [tex]m=\frac{-v}{u}[/tex]
[tex]-0.47=\frac{-14}{u}[/tex]
u=29.78 cm
Now for concave mirror [tex]\frac{1}{f}=\frac{1}{u}+\frac{1}{v}[/tex]
[tex]\frac{1}{f}=\frac{1}{14}+\frac{1}{29.78}[/tex]
[tex]\frac{1}{f}=0.105[/tex]
f=9.52 cm