A ray of light travels from a denser medium to a rarer medium. The reflected and the refracted rays are perpendicular to each other. If '$$r$$' and '$$r_1$$' are the angle of reflection and refraction respectively and '$$\mathrm{C}$$' is the critical angle, then the angle of incidence is
A convex lens of focal length 'F' produces a real image 'n' times the size of the object. The image distance is
There are four convex lenses $$L_1, L_2, L_3$$ and $$L_4$$ of focal length $$2,4,6$$ and 8 cm, respectively. Two of these lenses from a telescope of length 10 cm and magnifying power 4. The objective and eye lenses are respectively
Refractive index of the medium is $$\mu$$ and wavelength is $$\lambda$$, then which of the following proportionality relation is correct?