Question

what signs(+ve or -ve) to use during mirror and lens numericals
plz answer in context to Focal length, object size and image size

Answer 1

+ve mirror formula is right

Answer 2

IF mirror is concave

+ve values

object size

-ve values

image size
image distance
object distance
focal length


if mirror convex

+ve values

focal length
image height
image distance
object height

-ve values

object distance


if lens is concave

all distances negative

all sizes positive


if lens is convex

+ve values

focal length
image distance
object height

- ve values

object distance
image height


HOPE THIS HELPS U