Will the image of the object be on the right side or left side of the lens?

Question

Suppose that you have a converging lens with a focal length of 20 cm and you place a small object at a distance of 25 cm to the right of the lens. I understand the image will be real so just not sure if left or right. Also, how do you find the distance of the image from the lens? Please show your work, thanks!

Answer 1

Hi, Uswah

By convention the object is usually placed at the left of the lens, but the image for a converging lens is always on the opposite side of the lens from the object if the object distance is greater than the focal length.

To find the image distance, use the thin lens formula: 1/f = 1/p + 1/q where f is focal length, p is object distance, and q is image distance. You already know f and p, so solve for q.