(a) Object distance (u) for a concave mirror or convex mirror:
Positive sign (+): The positive sign for the object distance (u) indicates that the object is located on the same side as the incident light rays (the side from which the light rays come before reflecting off the mirror). This means the object is in front of the mirror.
Negative sign (-): The negative sign for the object distance (u) indicates that the object is located on the opposite side of the incident light rays (the side towards which the light rays travel after reflecting off the mirror). This means the object is behind the mirror.
For a concave mirror, when the object is located on the same side as the incident light rays (in front of the mirror), the object distance (u) is positive. When the object is on the opposite side of the incident light rays (behind the mirror), the object distance (u) is negative.
For a convex mirror, the object distance (u) is always positive, as the object is always in front of the mirror.
(b) Image distance (v) for a concave mirror:
Positive sign (+): The positive sign for the image distance (v) in a concave mirror indicates that the image is formed on the same side as the outgoing light rays (the side towards which the light rays travel after reflecting off the mirror). This corresponds to a real image, which can be projected on a screen.
Negative sign (-): The negative sign for the image distance (v) in a concave mirror indicates that the image is formed on the opposite side as the outgoing light rays (the side from which the light rays appear to originate without actually converging to form an image). This corresponds to a virtual image, which cannot be projected on a screen but is perceived as if it is coming from a specific location behind the mirror.
(c) Image distance (v) for a convex mirror:
Positive sign (+): The positive sign for the image distance (v) in a convex mirror indicates that the image is formed on the same side as the outgoing light rays (the side towards which the light rays travel after reflecting off the mirror). This corresponds to a virtual image, which cannot be projected on a screen but is perceived as if it is coming from a specific location behind the mirror.
Negative sign (-): Convex mirrors always produce virtual images that are smaller and located closer to the mirror than the actual object. Hence, the image distance (v) for a convex mirror is always negative. The negative sign indicates that the virtual image is formed on the opposite side as the outgoing light rays (the side from which the light rays appear to originate without actually converging to form an image).
