Question

Assuming the principal axis as the x-axis and the optical centre as the origin ,how will you determine the signs od quantities u,v and f for a lens

Answer 1

Answer:

u= -ve

v= +ve if image is virtual and -ve if image is real

f= +ve if the lens is concave and -ve if the lens is convex

Answer 2

Answer:

signs will be different for different cases.

Explanation:

In case of convex lens:-

u- negative

v- if left then negative and if right then positive

f- positive

In case of concave lens:-

u- negative

v- always negative

f- negative