Question

All distances parallel to the principal axis are measured from the ____________ of the mirror

Answer 1

all distances parallel to the principal axis are measured from the $\underline{pole}$ of the mirror.

object distance : distance of object from the pole of the mirror is known as object distance.it is denoted by u.
image distance : distance of image from the pole of the mirror is known as image distance.it is denoted by v.
focal length : distance of focus from the pole of mirror is known as focal length and it is denoted by f.

here it is clear that all distances parallel to the principle axis are measured from the pole of the mirror.

Answer 2

Answer:

all the distances are measured from the pole of the mirror.

Explanation:

1. image distance - the distances of the image fron the mirror and image is called image distance. it is denoted by v.

2. object distance = the distances between the mirror and the object is called object distance . it is denoted by u.

3. mirror formula

1/v + 1/u = 1/f

where , f is the focal length of ten mirror.

* note - focal length of concave is taken as -ve

and that of convex mirror is + ve.