In the context of the formation of images by spherical mirror, which of the following statements are correct?

(A) Magnification m is +ve for real images and -ve for virtual images.
(B) f and R are -ve for a concave mirror and +ve for a convex mirror.
(C) Magnification m has no units.
(D) For a real object, u is +ve and v is +ve for real image and -ve for virtual image.

Choose the correct answer from the options given below:

(B) and (C) only

The correct answer is Option (4) → (B) and (C) only

Check each statement:

(A) Wrong → For mirrors, $m$ is negative for real images and positive for virtual images.

(B) Correct → By sign convention, $f$ and $R$ are negative for concave mirror, positive for convex mirror.

(C) Correct → Magnification is a ratio (dimensionless), so no units.

(D) Wrong → For a real object, $u$ is taken negative; for real image $v$ is negative, and for virtual image $v$ is positive.

Answer: (B) and (C) are correct.