Ray Optics and ...

Colour of the sky is blue due to

A simple magnifying lens is used in such a way that an image is formed at $25\ cm$ away from the eye. In order to have $10$ time magnification, the focal length of the lens should be 

Which of the following event is not related to refraction of light ?

The apreture  of  astronomical telescope is large because .

Choose the correct alternative:
A ray of light make an angle of $50^{\circ}$ with the surface $S_{1}$ of the glass slab. Its angle of incidence will be__________

A uniform, horizontal beam of light is incident upon a prism as shown in the fig. The prism is in the shape of a quarter cylinder of radius R $=$ 5cm, and has a refractive index $\dfrac{2}{\sqrt{3}}$. A patch on the table for a distance x from the cylinder is unilluminated. The value of x is

The refracting angle of a prism $60^{\mathrm{o}}$.The refractive index of the material of the prism is $\sqrt{\dfrac{7}{3}}$. The limiting angle of incidence of a ray that will be transmitted through the prism in this case will be :

A ray of light enters at grazing angle of incidence into an assembly of three isosceles right-angled prisms having refractive indices $\mu_{1}=\sqrt{2}, \mu_{2}=\sqrt{x}$ and  $\mu_{3}=\sqrt{3}$ . If finally emergent light ray also emerges at grazing angle then calculate x :

Refractive indices of 2 different media with separating boundary at the diagonal of rectangular glass slab are shown. Total angle of deviation of the ray as shown in the figure, when it emerges in air is :

A thin convex lens made of glass of  $\mu =$ 1.5 has refracting surfaces of radii of curvature 10 cm each. The left space of lens contains air and the right space is filled with water of refractive index $\dfrac{4}{3}$. A parallel beam of light is incident on it. The position of the image is :