Question

An object is placed at a distance of 10 cm from a concave mirror of radius of curvature 0.6 m. Which of the following statement is incorrect?

• A. The image is formed at a distance of 15 cm from the mirror.
• B. The image formed is real.
• C. The image is at 1.5 times the distance of the object.
• D. The image formed is virtual and erect.

Answer 1

The correct option is B The image formed is real.

Given :
Radius of curvature $R$ = 0.6 m = 60 cm
Let $f$ be the focal length
We know that
$f=\frac{R}{2}$
$f=30cm$
For a concave mirror, focal length is taken as negative
i.e $f=-30cm$

Object distance $u=-10cm$
Let $v$ be the image distance
Using mirror formula,
$\frac{1}{\text{f}}$ = $\frac{1}{\text{v}}$ + $\frac{1}{\text{u}}$
$\frac{1}{\text{-30}}$ = $\frac{1}{\text{v}}$ + $\frac{1}{\text{-10}}$
$\Rightarrow v=15cm$