Answer
In the closest mirror $\mathrm{M}_1$, the "first" image $I_1$ is $10 \mathrm{~cm}$ behind $\mathrm{M}_1$ and therefore $20 \mathrm{~cm}$ from the object $O$. This is the smallest distance between the object and an image of the object.
Work Step by Step
In the closest mirror $\mathrm{M}_1$, the "first" image $I_1$ is $10 \mathrm{~cm}$ behind $\mathrm{M}_1$ and therefore $20 \mathrm{~cm}$ from the object $O$. This is the smallest distance between the object and an image of the object.
