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 mirrorThe focal length of a spherical mirror is double of its radius of curvatureA ray of light travelling from a rarer medium to a denser medium bends away from the normal