Question

for finding the focal length of a convex lens where do we keep the object and what kind of image do we obtain??

Answer 1

We always keep object in left side and image we obtain can be real and inverted or virtual and erect

Answer 2

To find the focal Length of a convex lens , We will incident parallel rays (rays from a far distance source like sun ) on the lens and measure the distance where the rays focus as point. it will be the Focal length .