Which one of the following statements is correct?
The image formed by a concave mirror for an object lying at infinity is at the principal focus, highly diminished, real and inverted.
A ray of light parallel to the principal axis after reflection from a concave mirror appears to diverge from the principal focus of the mirror.
The focal length of a spherical mirror is double of its radius of curvature.
A ray of light travelling from a rarer medium to a denser medium bends away from the normal.
Answer is Wrong!
Answer is Right!
This question was previously asked in
UPSC NDA-2 – 2015
A) The image formed by a concave mirror for an object lying at infinity is indeed formed at the principal focus (F), is highly diminished (essentially a point image), and is real and inverted. This statement accurately describes the image formation for a concave mirror when the object is at infinity.
C) The focal length (f) of a spherical mirror is half of its radius of curvature (R), i.e., f = R/2. The statement says it is double, which is incorrect.
D) A ray of light travelling from a rarer medium to a denser medium bends *towards* the normal, not away from it. Bending away from the normal occurs when light travels from a denser medium to a rarer medium.
Therefore, only statement A is correct.