For most stand magnifiers, the object is located inside the primary focal point of the lens.

For most stand magnifiers, the object is located inside the primary focal point of the lens.

• A. Inside the primary focal point
• B. Outside the primary focal point
• C. At the focal point
• D. Beyond the focal length

Answer: (A)

Placing the object inside the focal length of a convex lens produces a magnified, upright virtual image. That’s the behavior stand magnifiers rely on: when the object is closer to the lens than the focal point, the lens cannot project a real image onto a screen, but instead the rays diverge as if coming from a larger image located on the same side as the object. Your eye sees this virtual image at a comfortable distance and magnified, which is ideal for near tasks like reading. If the object were outside the focal point, you’d get a real, inverted image on the other side of the lens, which isn’t how a simple magnifier is used for viewing text. At the focal point itself, the emerging rays are parallel, making the image appear at infinity—unhelpful for close, comfortable viewing. Beyond the focal length yields a real, inverted image as well, again not suitable for the typical magnifying effect.

Placing the object inside the focal length of a convex lens produces a magnified, upright virtual image. That’s the behavior stand magnifiers rely on: when the object is closer to the lens than the focal point, the lens cannot project a real image onto a screen, but instead the rays diverge as if coming from a larger image located on the same side as the object. Your eye sees this virtual image at a comfortable distance and magnified, which is ideal for near tasks like reading.

If the object were outside the focal point, you’d get a real, inverted image on the other side of the lens, which isn’t how a simple magnifier is used for viewing text. At the focal point itself, the emerging rays are parallel, making the image appear at infinity—unhelpful for close, comfortable viewing. Beyond the focal length yields a real, inverted image as well, again not suitable for the typical magnifying effect.