A mirror forms an image which is 30cm from an object and twice its height.
- Where must the mirror be situated?
- What is the radius of curvature?
- Is the mirror convex or concave?
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Let the image formed is virtual and erect.v - u = 30cm
m = 2
$\Rightarrow{\text{v}}=2{\text{u}}$
$2\text{u}-\text{u}=30\text{cm}$
$\text{u}=-10\text{cm}$
$\frac{1}{\text{f}}=\frac{-1}{20}$
$\text{f}=-20\text{cm}$
$\text{R}=2\text{f}=-40\text{cm}$
m = 2
- $\text{m}=-\frac{\text{v}}{\text{u}}$
$\Rightarrow{\text{v}}=2{\text{u}}$
$2\text{u}-\text{u}=30\text{cm}$
$\text{u}=-10\text{cm}$
- $\text{v}=-2\text{u}=20\text{cm}$
$\frac{1}{\text{f}}=\frac{-1}{20}$
$\text{f}=-20\text{cm}$
$\text{R}=2\text{f}=-40\text{cm}$
- Concave mirror.
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