A bracken fern spore produces an image that is 7.5 cm tall when placed before a converging lens of focal length 6.0 cm.If the spore's true height is 1.5 mm,how far from the lens was its image?
A)3.1 m
B)2.9 m
C)30 cm
D)3.3 cm

Question

Quizplus · Accepted Answer

The image is virtual and 7.5 cm tall, so the magnification is 7.5 cm / 1.5 mm = 5. The object distance is then 6 cm / 5 = 1.2 cm. The image distance is then 1 / (1 / 6 cm - 1 / 1.2 cm) = 3.1 m.

A Bracken Fern Spore Produces an Image That Is 7