Question

The graph shows two curves between power $\left(P\right)$ and focal length $\left(f\right)$. The correct option(s) for the type of mirror is (are):

• A. Curve $-A$ is for convex mirror
• B. Curve $-B$ is for concave mirror
• C. Curve $-B$ is for convex mirror
• D. Curve $-A$ is for concave mirror

Answer 1

Answer: (A), (B)

Curve $-B$ is for concave mirror

We know that, power of a spherical mirror is given by,
$P=-\frac{1}{f}$
where $f$ is focal length.

$\Rightarrow Pf=-1$
So, it represents a rectangular hyperbola.

For curve$-A$, focal length is positive and power is negative. Thus, it represents a convex mirror.

For curve$-B$, focal length is negative and power is positive. Thus, it represents a concave mirror.

Hence, options $\left(a\right)$ and $\left(b\right)$ are correct.