Four lenses are made of glass and the radius of curvature of each face is given below. Which will have the greatest focal power

Four lenses are made of glass and the radius of curvature of each face

1.	Four lenses are made of glass and the radius of curvature of each face is given below. Which will have the greatest focal power
Answer» 10CM CONVEX and 15CM convex 5cm convex and 10cm CONCAVE 15cm concave and plane 20cm convex 30CM concave Answer :A