An object approaches a convergent lens from the left of the lens with a uniform speed 5 m/s and stops at the focus. The image A. moves away from the lens with a uniform speed 5 m/s. B. moves away from the lens with a uniform acceleration. C. moves away from the lens with a non-uniform acceleration. D. moves towards the lens with a non-uniform acceleration.

Question

Philoid · Accepted Answer

When the object is at focus, the rays are parallel. The image is formed at infinity. When the object in at infinity, the image is formed at focus. As you bring an object from far away towards focus, the image moves away from the focus towards infinity. Hence, it moves away from the lens. Also, when moving the object with constant velocity, the object moves with non-uniform acceleration.