Question
An object is 24cm away from a concave mirror and its image is 16cm from the mirror. Find the focal length and radius of curvature of the mirror, and the magnification of the image.
✓
Answer
u = -24cm
v = -16cm
f = ?, m = ?
We know that
$\frac{1}{\text{v}}+\frac{1}{\text{u}}=\frac{1}{\text{f}}$
$\frac{1}{-16}+\frac{1}{-24}=\frac{1}{\text{f}}$
$\frac{-5}{48}=\frac{1}{\text{f}}$
$\text{R}=2\text{f}$
$=2\times-9.6=-19.2\text{cm}$
$\text{m}=-\frac{\text{v}}{\text{u}}$
$\text{m}=-\frac{-16}{-24}$
$\text{m}=-0.666$
v = -16cm
f = ?, m = ?
We know that
$\frac{1}{\text{v}}+\frac{1}{\text{u}}=\frac{1}{\text{f}}$
$\frac{1}{-16}+\frac{1}{-24}=\frac{1}{\text{f}}$
$\frac{-5}{48}=\frac{1}{\text{f}}$
$\text{R}=2\text{f}$
$=2\times-9.6=-19.2\text{cm}$
$\text{m}=-\frac{\text{v}}{\text{u}}$
$\text{m}=-\frac{-16}{-24}$
$\text{m}=-0.666$
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