Question

An object is moved along the principal axis of a converging lens from a position 5 focal lengths from the lens to a position that is 2 focal lengths from the lens. Which statement about the resulting image is most accurate?

• A. The image increases in size and decreases in distance from the lens
• B. The image increases in size and increases in distance from the lens
• C. The image decreases in size and decreases in distance from the lens
• D. The image decreases in size and increases in distance from the lens

Answer 1

Answer: (B)

The image increases in size and increases in distance from the lens

The easiest way to answer this question is with a fast sketch. For a given object's position, draw two rays from the top of the object. One ray is parallel to the principal axis and passes through the focal point on the opposite side of the lens. The other ray passes through the centre of the lens. The top of the image appears where these two rays intersect.
Change the object's position and repeat the process. You will observe that as the object approaches the lens while remaining beyond the focal length, the image produced on the opposite side of the lens moves away from the lens and increases in size. And the image is real and inverted.