Question

The linear magnification for a spherical mirror is the ratio of the size of the image to the size of the object, and is denoted by m. Then m is equal to (symbols have their usual meanings)

• A. $\frac{u}{u-f}$
• B. $\frac{uf}{u-f}$
• C. $\frac{f}{u+f}$
• D. None of these

Answer 1

The correct option is C $\frac{f}{u+f}$

General equation for a spherical mirror says that:
$\frac{1}{v}+\frac{1}{u}=\frac{1}{f}$

$\frac{u}{v}-1=\frac{u}{f}$

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

$\frac{v}{u}=\frac{f}{u+f}=m$ (magnification)