# An object is placed 11 cm in front of a convex mirror of focal length 4 cm. Using the lens...

## Question:

An object is placed 11 cm in front of a convex mirror of focal length 4 cm.

Using the lens equation, find where the image will form and state whether it is a real or virtual image.

## Convex Mirrors

We need to remember that a convex mirror is a diverging mirror and the focus is located behind the mirror. Thus, the focal length must be negative. We can use the equation:

{eq}\frac{1}{s_o}+\frac{1}{s_i}=\frac{1}{f} {/eq}

to determine the location of an image.

Also, a convex mirror can only produce images that are smaller upright and virtual.

This is a convex mirror so we must remember that the focal length is negative.

Given and Equation:

{eq}s_o=11 \ cm\\ f=-4 \ cm\\ \\ \frac{1}{s_o}+\frac{1}{s_i}=\frac{1}{f}\\ \frac{1}{11 \ cm}+\frac{1}{s_i}=\frac{1}{-4 \ cm}\\ s_i=-2.93 \ cm\\ {/eq}

A negative image distance means that the image is located behind the mirror and is virtual. 