Electromagnetic waves emanating from a point A (in air) are incident on a rectangular block of material M and emerge from the other side as shown. The angles i and r are angles of incidence and refraction when the wave travels from air to the medium. Such paths for the rays are possible
(A) if the material has a refractive index very nearly equal to zero.
(B) only with gamma rays with a wavelength smaller than the atomic nuclei of the material
(C) if the material has a refractive index less than zero.
(D) only if the wave travels in M with a speed faster than the speed of light in vacuum.
