Question

A candle at left of a double convex lens has a blue line straight from the tip of the its flame to near the top left of the lens and then down and right through a point on a line running through the center of the lens. An orange line from the tip of the lens runs down and right through the center of the lens to intersect the blue line below the centerline of the lens below the centerline. A green line runs down and right from the tip of the flame through a point to the left of the lens on the centerline to the bottom part of the lens and then straight to intersect the blue and orange lines. Where the three lines intersect, a reduced inverted image of the candle is seen.
How can the image be described? Check all that apply.

smaller than the object
real
right-side up
larger than the object
upside down
virtual

Answer 1

Choose:
- smaller than the object — Yes
- real — Yes
- upside down — Yes

Not applicable:
- right-side up — No
- larger than the object — No
- virtual — No

Reason: the three refracted rays actually meet on the lens's far side (so the image is real), they meet below the optical axis (so the image is inverted/upside down), and the intersection is a reduced image (so smaller than the object), which is the situation for an object beyond 2f of a converging lens.