Convex Mirrors images help

[whitehorsey]

1. Shiny lawn spheres placed on pedestals are convex mirrors. One such sphere has a diameter of 40 cm. A 12 cm robin sits in a tree 1.5 m from the sphere.
a) Where is the image of the robin?
b) How long is the robin's image?




2. 1/f = 1/d_o + 1/d_i



3. a. 1/f = 1/d_o + 1/d_i
d_i = d_of/1/f = d_o - f
= 150(10)/ 150 -10
= 10.71 cm
b. m = h_i/h_o = d_i/d_o
h_i = h_o (d_i/d_o)
= 12(-10.71/150)
= -0.857 cm
I'm not sure if this is right.

 

[rl.bhat]

Focal length of the convex mirror should be taken as negative.

 

[whitehorsey]

Thank You!