Question

A diverging lens of -30 cm focal length produced an image which is 1/3 the height of the object. What would be the distance of the image?

Answer 1

Answer on question #61811, Physics / Optics

Question A diverging lens of -30 cm focal length produced an image which is 1/3 the height of the object. What would be the distance of the image?

Solution Magnification is related to heights and distance to images as

$M=\frac{h_{i}}{h_{o}}=\frac{d_{i}-f}{f}$

In our case $h_{i}/h_{o}=1/3$, $f=-30$. Hence, distance to object is

$d_{i}=f\cdot\frac{h_{i}}{h_{o}}+f=-30/3-30=-40\,cm$