Question

An object is placed at a distance of $150cm$ from a concave lens of focal length $120cm$. Find the nature of the image.

• A. Erect and virtual
• B. Real and invented
• C. Erect and real
• D. None

Answer 1

The correct option is A Erect and virtual

Given, $u=-150cm$ and $f=-120cm$

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

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

$⟹\frac{1}{v}=\frac{-1}{120}-\frac{1}{150}$

$⟹v=\frac{-600}{9}cm$

Hence, magnification $=\frac{v}{u}>0$

Hence, image is erect and virtual.

Answer-(A).