A shop security mirror 5.0m from certain items displayed in the shop produces one-tenth magnification.
  1. What is the type of mirror?
  2. What is the radius of curvature of the mirror?
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  1. It is a convex mirror, as it has a wide area of view.
  2. Given,
Distance of the object (u) = -5 m

Magnification (m) = $\frac{1}{10}$

We have to find the position of the image (v), radius of curvature (R) and the focal length of the mirror (f).

Using the magnification formula, we get

$\text{m}=\frac{\text{-v}}{\text{u}}$

$\text{m}=\frac{\text{-v}}{-5}$

$\frac{1}{10}=\frac{\text{-v}}{-5}$

$\frac{1}{10}=\frac{\text{v}}{5}$

$\text{v}=0.5\text{m}$

Now, using the mirror formula, we get

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

$\frac{1}{\text{f}}=\frac{1}{-5}+\frac{1}{0.5}$

$\frac{1}{\text{f}}=\frac{1}{-5}+\frac{10}{5}$

$\frac{1}{\text{f}}=-\frac{1}{5}+\frac{10}{5}$

$\frac{1}{\text{f}}=-\frac{9}{5}$

$\text{f}=\frac{5}{9}$

$\text{R}=2\text{f}$

or $\text{R}=1.1$

Therefore, the radius of curvature of the mirror (R) is 1.1m.
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