In an optics lab

PHYSICS · Single correct · AP · Physics 2: Algebra-based · Geometric Optics · Geometric Optics

Problem

In an optics lab, students vary the object distance

s_o

for a thin lens and record the corresponding image distance

s_i

. They plot

\frac{1}{s_i}

on the vertical axis versus

\frac{1}{s_o}

on the horizontal axis and obtain a best-fit line with slope

-1.02

and vertical intercept

0.050\,\text{cm}^{-1}

. Based on the graph, what is the best estimate of the lens’s focal length? (a)

-20\,\text{cm}

(b)

20\,\text{cm}

(c)

10\,\text{cm}

(d)

0.98\,\text{cm}