Question

How we can identify a concave mirror or a convex mirror has which sign + or _
plz tell me

Answer 1

Cancave mirror always has a negetive sign as focal lenght and convex always has a positive sign

Answer 2

Concave mirror has (-) sign as it's image is real and inverted and focal length is also negative
Convex mirror has (+) as its image is virtual and erect and focal length is also positive
Hope it helps...