Question

I use a cosmetic mirror to magnify my eyelashes. My 1.2-cm long eyelashes are magnified to 1.6 cm when placed 5.8 cm from the mirror, how can I determine the image distance for such an upright image?

Answer 1

oh! that's easy

$magnification= \frac{ht. \: of \: image}{ht.of \: object} = - \frac{v}{u} \\ \frac{1.6}{1.2} = \frac{ - (v)}{( - 5.8) } \\ v = 7.73cm$

hope it helps(^～^)