In convex mirrors, the principal axis is the same as in a plane or concave mirror, perpendicular to the center of the mirror. In this case, the focal point is behind the mirror. A convex mirror has a negative focal length because of this. The focal point is the same distance from the mirror as in a concave mirror. This is shown in.

Focal .Length

10cm  

15 cm    

20 cm

30cm  

50cm

100CM

Convex             Diameter

B (i)                     50mm

B (ii)             60 mm

B (iii)             75 mm

B (iv)             100 mm