Read the following paragraph and answer the question. Give ONLY the answer, no other words or explanation.

For example:

Answer: <most likely answer, as short as possible>.

Paragraph: 
The focal length , , of a lens or mirror is the distance from the surface of the lens or mirror to the place where the light is focused. This is called the focal point or focus . For diverging lenses or mirrors, the focal length is negative.


Question: What type of lens and mirrors have a negative focal length?
diverging
Diverging lenses and mirrors.