Given :
The focal length of a concave mirror is 18 cm.
To Find :
The radius of curvature of the concave mirror.
Solution :
We know,

Therefore, the radius of curvature of concave mirror is 36 cm.
Hence, this is the required solution.
Self productive and it depends on how whom is behaving.
I believe the answer is californium because it is used in most metals and is very strong and expensive like gold and silver
A. more quickly. example lightning (light) comes first in a storm. then thunder (sound) comes after