What is the minimum number of rays required for locating the image formed by a concave mirror for an object? Draw a ray diagram to show the formation of a virtual image by a concave mirror.
(i) At least two rays are required for locating the image formed by a concave mirror for an object.
(ii) 
here, RQ is the object, R’Q’ ⇒ virtual image, BPA is the concave mirror.
F is the focus of the concave mirror. C is the centre of curvature of the mirror.