Questions 15 to 17 are based on the following write up If Snell s law is found valid for two mediums whose refractive indices have opposite signs the incident and the refracted rays must remain on the same side of the normal at the point of incidence In the figure is shown a ray crossing the interface between two mediums I and II The ray makes angles and 0 with normal in the medium I and II The refractive indices of the mediums 1 and 2 have opposite signs Snell s law is expressed for the above situation as usual by the equation sint sin 0 Therefore to satisfy this equation the angles and must also have opposite signs 5 A self luminous point object placed at a distance x from a slab of transparent material of negative refractive index is viewed through the slab as shown in the figure Thickness of the slab is d refractive index of material of the slab with respect to the outside medium is 1 For different moduli of values of x and d the observer may find real or virtual image of the object Which of the following statements is true a If x d image is virtual and for x d image is real b If x d image is virtual and for x d image is real c If x d image is virtual and for x d image is real d If x d image is virtual and for x d image is real Object 16 Suppose a virtual object instead of a real object is at a distance x from the surface A of the slab Now which of the following statements is true a For the cases x d and x da real and erect image is formed outside the slab b For the cases x d and x d a real and inverted image is formed outside the slab virtual e If x d a real image is formed outside the slab and for x d a image is formed inside the slab d If x d a real image is formed and for x d a virtual image is formed in both the cases the image is outside the slab A 0 Medium Slab 0