Question

An object in front of a concavemirror with f = 15.0 cm forms animage at -6.33 cm. Find theobject distance.(Mind your minus signs.)(Unit = cm)

Answer 1

Answer:

The object distance = 4.45 cm

Explanation:

Given

The focal length, f = 15.0 cm

The image distance, v = -6.33 cm

The object distance, u = ?

The focal length, object distance, image distance are related by the formula:

$\begin{gathered} \frac{1}{f}=\frac{1}{u}+\frac{1}{v} \\ \\ \frac{1}{15}=\frac{1}{u}-\frac{1}{6.33} \\ \\ \frac{1}{u}=\frac{1}{15}+\frac{1}{6.33} \\ \\ \frac{1}{u}=0.22464454976 \\ \\ u=\frac{1}{0.22464454976} \\ \\ u=4.45\text{ cm} \\ \end{gathered}$

The object distance = 4.45 cm