Giving reasons, state the ‘signs’ (positive or negative) which can be given to the following :
(a) object distance (u) for a concave mirror or convex mirror
(b) image distances (v) for a concave mirror
(c) image distances (v) for a convex mirror
(a) Object distance (u) for a concave mirror or convex mirror is always negative because an object is always placed to the left side of the mirror and the distances towards the left of the mirror are always negative.
(b) In case of a concave mirror, if the image is formed on the left side of the mirror, then the image distance (v) will be negative and if the image is formed on the right side of the mirror, then the image distance (v) will be positive. This is because distances measured to the left of the mirror are negative and to the right of the mirror is positive.
(c) Image distances (v) for a convex mirror is always positive because the image is always formed behind the mirror.