Question

Which of the following is a correct graph between object distance$\left(u\right)$ and image distance $\left(v\right)$ for a concave mirror as per the sign convention?

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

In case of concave mirror for virtual objects, the object distance is +ve and the corresponding image formed will be real (image distance will be -ve)

For real objects,
Both object distance $\left(u\right)$ and image distance $\left(v\right)$ are negative.

When the object approaches $-\infty$, the image is formed at focus $\left(F\right)$.



The graph of $u$ vs $v$ will be never a straight line because
$\frac{1}{u}+\frac{1}{v}=\frac{1}{f}$
The lines indicating $-\infty$ and $+\infty$ will be asymptotic as $\frac{1}{u}\to 0$ and $\frac{1}{-v}\to \frac{1}{-f}$ when $u\to -\infty$
Thus, correct option is (a)