Question

A 7.5 cm tall Aragorn action figure is placed 12.4 cm in front of a double convex lens. If the image of Aragorn is located 7.5 from the lens, what is the focal length of the lens?

Answer 1

Answer:

f = 4.67 cm

Explanation:

Here, we can use the thin lens formula, as follows:

$\frac{1}{f}= \frac{1}{p}+ \frac{1}{q}$

where,

f = focal length of lens = ?

p = distance of object from lens = 12.4 cm

q = distance of image from lens = 7.5 cm

Therefore,

$\frac{1}{f} =\frac{1}{12.4\ cm} +\frac{1}{7.5\ cm}\\\\\frac{1}{f} = \frac{1}{4.67\ cm}$

f = 4.67 cm