Question

Mark correct option or options :

• A. The minimum distance between a real image and the real object in concave mirror is zero
• B. The minimum distance between a real object and real image in concave mirror is greater than 4f, where f is focal length of the lens
• C. The focal length of concave mirror depends upon the wavelength of light incident on it.
• D. The focal length of mirror depends upon medium in front of the mirror

Answer 1

The correct option is A The minimum distance between a real image and the real object in concave mirror is zero

The minimum distance between an object and its real image in the case of a concave mirror is Zero. When the object is at the 2F distance i.e. the center of curvature, then the image is real and formed inverted at the same distance.
So option A is correct.
For other options we know that focal length only depends on the radius of the mirror.