Question

A point object is kept at the first focus of a convex lens. If the lens starts moving towards right with a constant velocity, the image will

• A. always move towards right
• B. always move towards left
• C. first move towards right & then towards left
• D. first move towards left & then towards right

Answer 1

The correct option is D first move towards left & then towards right

If the object is placed constant at a particular position, as the lens is moved towards the right, the object distance increases more than f. So, the image starts coming towards the optical centre from $\infty$ i.e moves towards the left.
However, once the object moves within the focal length of the lens, the image starts moving towards the right as a virtual image is now being formed