Question

An object is kept on the principal axis of a concave mirror of focal length $10$cm, at a distance of $15$cm from its pole. The image formed by the mirror is?

• A. Virtual and magnified
• B. Virtual and diminished
• C. Real and magnified
• D. Real and diminished

Answer 1

Answer: (C)

Real and magnified

Focal length of concave mirror $f=-10cm$
Object distance $u=-15cm$
Using $\frac{1}{v}+\frac{1}{u}=\frac{1}{f}$
$\therefore$ $\frac{1}{v}+\frac{1}{-15}=\frac{1}{-10}$
$⟹v=-30cm$
Since $v$ is negative, so image formed is real.
Magnification $m=\frac{-v}{u}$
$\therefore$ $m=-\frac{(-30)}{-15}=-2$
Since $m$ is greater than $1$, so magnified image is formed.
Correct answer is option C.