Answer:

a. concave mirror

b ?

i.Centre of Curvature: The centre of the sphere of which the mirror forms the part. Represented by “C”.

ii. Aperture: The diameter of the spherical mirror is called its aperture. The reflecting surface of the mirror.

iii. Pole: The centre of reflecting surface. It is represented by letter P.

Explanation:

1. The dentist uses a CONCAVE MIRROR to observe a magnified image of the tooth. As we know, a concave mirror forms a virtual, erect and magnified image
2. the mirror is used by dentist is concave mirror.
3. Pole: The middle point of the reflecting surface of a spherical mirror is called pole. The letter P represents pole, MP = M'P. Centre of curvature: It is the centre of the sphere of glass of which the mirror is a part. ... Principal focus: The mid-point of CP is called focus (F).
4. (i) Pole of a spherical mirror. The central point of the reflecting surface of a spherical mirror is termed as the pole. It lies on the mirror and is denoted by the letter (P).