Question

An object is kept at a distance of $15cm$ from a concave mirror whose radius of curvature is $30cm$. What is the position of the image?

Answer 1

step 1

Given that, object distance, $u=-15cm$

The radius curvature of the mirror, $R=-30cm$

The focal length of the mirror, $f=\frac{R}{2}=-15cm$

Let $v$ be the image distance from the mirror.

step 2

Applying the mirror formula $\frac{1}{f}=\frac{1}{v}+\frac{1}{u}$, we get,

$$\begin{gathered} \Rightarrow \frac{1}{-15}=\frac{1}{v}+\frac{1}{-15} \\ \Rightarrow \frac{1}{v}=0 \\ \Rightarrow v=\infty \end{gathered}$$

Hence, the image is formed at infinity.