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Question
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 distance (v) for a concave mirror
(c) image distance (v) for a convex mirror
Solution
(a) Object distance (u) for a concave or convex mirror is given a negative sign. This is because, the object is always placed to the left of the mirror.
(b)
- The image distance (v) for a concave mirror is given a positive sign if the image formed is behind the mirror and to the right of it.
- The image distance (v) for a concave mirror is given a negative sign if the image formed is in front of the mirror and to the left of it.
(c) The image distance (v) for a convex mirror is always given a positive sign because the image is always formed behind the mirror and to the right of it.
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