Question

4. An image formed by concave mirror is located a distance of 32.0 cm in front of the mirror. Focal length of the mirror is 12.0 cm. Determine the object distance.

Answer 1

as we know that the given mirror is concave

so

u= -30cm

as we know that the mirror equation

$\frac{1}{f}=\frac{1}{v}+\frac{1}{u}$

$\frac{1}{-12}=\frac{1}{v}+\frac{1}{-32}$

$\frac{1}{-12}+\frac{1}{32}=\frac{1}{v}$

$\frac{1}{v}=\frac{12-32}{32\times12}$

$\frac{1}{v}=\frac{-20}{32\times12}$

$\frac{1}{v}=\frac{-5}{96}$

so object disance is 19.2 cm in front of the mirror