A tree has a height of 3.40 cm and is placed in front of a concave mirror. The image of the tree is inverted, 1.60 cm tall, and located 14.0 cm in front of the mirror. Find the focal length of the mirror.

Respuesta :

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