Question

Diamond. Thanks for the help. I will comment if the answer is INCORRECT in hopes that you can retry the problem before I give a negative rating.

Answer 1

The image of diamond is virtual.

Now from lens equation for focal length $\frac{1}{f}=\frac{1}{v}-\frac{1}{u}$

$-\frac{1}{5.05}=\frac{1}{v}+\frac{1}{10.9}$

   $-\frac{1}{5.05}-\frac{1}{10.9}=\frac{1}{v}$

Therefore image position is v= -3.45cm

from definition of magnification $m = \frac{h_{i}}{h_{o}}= \frac{v}{u}$

The height of image is h_i = 3.45x3.21/10.9 = 1.02cm