Question

A concave mirror has focal length $f.A$ convergent beam of light is made incident on it. Then the image distance $v$ is

• A. Zero
• B. less than T
• C. Equal to T
• D. more than T

Answer 1

Answer: (B)

We know that for a mirror $\frac{1}{v}=-\frac{1}{u}-\frac{1}{t}$
For convergent, $u$ is positive.
For concave mirror, $f$ is negative.
$\Rightarrow \frac{1}{v}=-\frac{1}{u}-\frac{1}{t}$
As, $u>>f$
$\Rightarrow \left[\frac{1}{v}>\frac{1}{f}\right]$
$\Rightarrow v<f$