Question

How is v positive? as we know all are distances measured from optical center and in this case image is real so it should have been negative

Answer 1

Answer:

Explanation:

In case of convex lens

V is positive

Answer 2

Shown , V is positive

•Signs are decided by following new Cartesian sign convetion.

•So , Cartesian Sign Convention are as follows:

1) All distances are measured from pole P

2) Distance measured in the direction of Incident Ray is taken as positive.

Distance measured again Incident Ray is taken as negative.

3) Distance above principal axis is taken as positive & distance against principal axis is taken as negative.

•So, If v is measured in the direction of Incident Ray then it should be positive

•If, V is measured against the direction of Incident Ray then it should be negative.