What type of mirror should be used:

(a) as a shaving mirror?
(b) as a shop security mirror?

The type of mirror that should be used

(a) as a shaving mirror is concave mirror

To shave the beard on our face properly and safely, we need to see an enlarged image of our face. This is why we should use a concave mirror because when an object is very close to it, a virtual, erect and enlarged image is formed.

(b) as a shop security mirror is convex mirror

Convex mirror is used for vigilance purpose in shops because it has a wider field of view and always form virtual, erect and small-sized images of the large number of objects at the same time.