Question

sign conventions for spherical mirrors .

Answer 1

Distances are to be measured from the pole (vertex) of the mirror .
Distances measured along the direction of the incident ray are positive. ...
Distances measured above the principal axis are positive.
the object distance is always negative
distances measured below the principal axis are negative

Answer 2

$\huge\mathfrak\red{Heya\:Mate}$

$\huge\sf{Here\:is\:your\:Answer:-}$

Sign Convention for Reflaction by Spherical Mirrors use the pole of the mirror as Origin. The principal axis of the mirror is taken as the x-axis of the coordinate system.

$\underline{The\: convention \:are \:as\: follows:-}$

✔️ The object is always placed to the left of the mirror.

✔️ All distance parallel to the principal axis are measured from the pole of the mirror.

✔️ All the distance measured to the right of the orgin are taken as positive while those measured to the left of the origin is taken as negative.

✔️ Distances measured perpendicular to and above the principal axis are taken as positive.

✔️ Distance measured perpendicular to and below the principal axis are taken as negative.

Hope it helps you!!