A point on the principal axis of a concave mirror. from Where a ray of light reflects back without any deflation. is:

Correct option is B

​The correct answer is (b) center of curvature.

• In a concave mirror, the point on the principal axis where a ray of light reflects without any deflection is the center of curvature.
• The center of curvature (C) is the point that is located at a distance equal to the radius of curvature from the mirror's surface. It is on the principal axis and lies in front of the mirror.
• When a ray of light passes through the center of curvature, it strikes the mirror at a normal angle (i.e., perpendicular to the mirror surface).
• Since the angle of incidence is zero, the ray reflects along the same path, without any deviation.

Information about other options:

• Infinity: A ray parallel to the principal axis, after reflection from a concave mirror, converges at the principal focus. However, a ray from infinity does not reflect without deviation at a single point on the principal axis.
• Pole: The pole is the geometric center of the mirror’s surface, and while it lies on the principal axis, rays from it do not reflect without deviation.
• Principal Focus: The principal focus is the point where rays parallel to the principal axis converge after reflection. A ray from the focus does not reflect without deviation; it spreads out.

Information Booster:

• The center of curvature is a key point in understanding the geometry of spherical mirrors, as it is the center of the sphere from which the mirror is a section.
• For a concave mirror, the center of curvature is located in front of the mirror, at a distance equal to the radius of curvature (2f, where f is the focal length).
  
• Concave mirrors are used in many applications, including shaving, lighting, and astronomy.