Question

after using the idea of ray tracing techniques to confirm that the image is virtual and upright and a distance, explain how a magnifying glass works. You should know that the eye is approximately 2.5 cm in diameter, and the nearest point to an object that an average eye can focus on is 25 cm.

Answer 1

A magnifying glass is a convex lens. Convex means curved outward, like the underside of a spoon or the dome of a sports stadium. It is the opposite of concave, or curved inward. A lens is something that allows light rays to pass through it and bends, or refracts, them as they do so. A magnifying glass uses a convex lens because these lenses cause light rays to converge, or come together.

A magnifying glass, in effect, tricks your eyes into seeing what isn't there. Light rays from the object enter the glass in parallel but are refracted by the lens so that they converge as they exit, and create a "virtual image" on the retina of your eye. This image appears to be larger than the object itself because of simple geometry: Your eyes trace the light rays back in straight lines to the virtual image, which is farther from your eyes than the object is and thus appears bigger.