A concave mirror has a focal length of 22 Cm. At which of the following distance should a person hold his face from this concave mirror so that it may act as a shaving mirror ?
(a) 45 cm
(b) 20 cm
(c) 25 cm
(d) 30 cm
Give reason for your choice.
20 cm, the image formed is erect and magnified only if the object is placed between the pole and focus of the concave mirror.