Question

An object is placed 3.00 cm in front of a concave lens with a focal length of 5.00 cm. Find the image distance.

Answer 1

ANSWER:

-1.88 cm

STEP-BY-STEP EXPLANATION:

The situation would be the following:

Given:

Object distance (u): -3 cm

Focal distance (f): -5 cm

Using the lens formula, we calculate the distance of the image:

$\begin{gathered} \frac{1}{v}-\frac{1}{u}=\frac{1}{f} \\ \\ \text{We replacing} \\ \\ \frac{1}{v}-\frac{1}{-3}=\frac{1}{-5} \\ \\ \frac{1}{v}\cdot \:15v-\frac{1}{-3}\cdot \:15v=\frac{1}{-5}\cdot \:15v \\ \\ 15+5v=-3v \\ \\ 5v=-3v-15 \\ \\ 8v=-15 \\ \\ v=-\frac{15}{8} \\ \\ v=-1.88\text{ cm} \end{gathered}$

The image distance is -1.88 cm