Question

Q1. Write and explain mirror formula for a
concave mirror . Explain a sign convention
used to derive the same. Why is a sign convention important?​

Answer 1

first of all sign convention is imp for solving numericals (in some sense)

mirror formula for both convex and concave lens is 1/f=1/v-1/u

and for both convex and concave mirrors it is

1/f=1/v+ 1/u

here second photo is for the sign conventions of lenses