Question

A concave mirror has a focal length of 0.25 m. If an object produces a virtual image 0.04 m from the mirror, where is it located?

Answer 1

using mirror's formula

$\frac1f=\frac1u+\frac1v$

$\frac{1}{-0.25}=\frac1u+\frac1{0.04}\\\frac1u=-29$

$u=-\frac{1}{29}m$

u=-0.034 m