Question

A diverging lens has focal length of -20 cm. How large is the image if the object is 5cm tall?

A diverging lens has a focal length of -20 cm. How large is the image if the object is 5 cm tall?this is the only given that was given

Answer 1

For a given lens in order to get image size, we first need to evaluate magnification m , which is defined as ratio of image distance ( q ) to the object distance (p).  

So to evaluate magnification we apply the relation  

1/q - 1/p = 1/f  

where f is focal length of the lens.

unless p or q is provided along with f we can't evaluate magnification,

Only one thing that we can say without any calculation, for a diverging lens image is always shorter than the object.

So , image will be less than 5 cm in height.