An object is placed at a distance of 30 cm in front of a concave mirror of focal length 10 cm. Calculate the distance of the image from the mirror.

The real image is formed at a distance of

15 cm

in front of the mirror.
The focal length of a concave mirror,

f = - 10 cm

and distance of object from the mirror,

u = - 30 cm

As per mirror formula,

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

we have

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

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

\Rightarrow

\frac{- 1}{10} + \frac{1}{30}

\Rightarrow

\frac{- 3 + 1}{30}

\Rightarrow

= \frac{- 2}{30}

\Rightarrow

= \frac{- 1}{15}

An object is placed at a distance of $30 cm$ in front of a concave mirror of focal length $10 cm$ . Calculate the distance of the image from the mirror.