Why is the focal length of a concave lens negative? - Quora
The focal length of a convex mirror is its radius of curvature. - YouTube
In the “New Cartesian Sign convention” for mirrors, the sign has been given that the concave mirror has a [[1]]focal length and a convex mirror has a [[2]]one. - Infinity Learn
Show with the help of a ray diagram that focal length of convex mirror is positive while that of concave mirror is negative. - Sarthaks eConnect | Largest Online Education Community
Spherical mirrors; and Refraction
SOLVED: Quantity Sign Positive (+) Negative (-) Object distance Real object Virtual object Image distance Real image Virtual image Focal ength Concave mirror Convex mirror (opposite side of o,i Radius of curvature