Question

help in answering this please

Answer 1

power of lens means the reciprocal of focal length.it is easier to use.+is for convex lens whereas - is for concave lens

Answer 2

power of convergence means to convergence and divergence the focus of the lens it is basically reciprocal of its focal length in metres negative focal length indicates that it is concave lens and more positive focal length indicates that it is convex lens